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Discussion Starter · #1 ·
I have a 98 single cab 2wd 2.4l. I started getting a misfire in cylinder 2 somewhere between my morning break at work and my lunch time. It shakes at idle and acceleration. Under acceleration the check engine light will flash. I figured maybe a dirty injector. So I went and got some fuel injector cleaner additive and dumped it in the tank. Seems like not enough fuel because on the way home if I ease off the throttle the check engine light stops flashing. So I'm thinking not enough fuel.

Checked the spark plug. Had normal buildup. Wasn't wet. And does spark. Swapped the coils around. And same result.

Checked compression. I'm at 175psi.

I thought well if the spark plug wasn't wet then maybe I'm not getting fuel. Checked the harness. I'm getting 12v constant and a switching ground side. I ohmd it out had 14.9ohms. So I rigged up a test stand and the injector sprayed 2 straight streams out. I then thought well maybe they're dirty so I took them to work and cleaned them in our ultrasonic tank. Got a new seal kit with screens. Put them back and purposely didn't label them to see if the misfire moved. It did not.

I know that my timing chain needs to be replaced. But is it possible that the timing chain jumped a tooth and the truck still runs. Just runs bad? Cuz if I Rev it up while parked, it smooths out. Also when the ac compressor kicks on it smooths out. I'm thinking, more load more fuel, more timing. I'm wondering what you guys think?
 

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Mambeau / Admin
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If the timing chain is overdue for replacement it's a prime suspect (jumped or not). However, I don't know why it would cause a misfire condition on cylinder #2 alone.

Did you inspect the valves on cylinder #2?

I suppose something wrong with the crankshaft and / or camshaft position sensor could explain it.

If you haven't already done so, the first thing to do is connect a tester to check for codes and to check the timing. I mention this because you didn't specify how you knew the misfire was in cylinder #2.
 

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Discussion Starter · #3 ·
If the timing chain is overdue for replacement it's a prime suspect (jumped or not). However, I don't know why it would cause a misfire condition on cylinder #2 alone.

Did you inspect the valves on cylinder #2?

I suppose something wrong with the crankshaft and / or camshaft position sensor could explain it.

If you haven't already done so, the first thing to do is connect a tester to check for codes and to check the timing. I mention this because you didn't specify how you knew the misfire was in cylinder #2.
I pulled the codes it was P0302. I have not inspected the valves. If the valves weren't seating properly wouldn't my compression numbers be low? Maybe the sensors but it's only throwing cylinder 2 misfire codes.

While it's running if I pull the injector connector off of cylinder 2 nothing changes. If I pull the spark off of cylinder 2 nothing changes. I can't find any vacuum leaks either. I'm going to check the charging system tomorrow to see if I'm not getting enough juice to the coils due to an alternator charging low. And also some other checks. I will report back after.
 

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Mambeau / Admin
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The P0302 is definitely specific to cylinder #2.

Any of the misfire codes can be triggered by a number of things. I notice the Engine Cooling Temp sensor and the Mass Air Flow (MAF) sensor are among these things, so remember these two items might conceivably be in the mix.
 

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Ok, so you said you have spark on number 2. The likely hood is the injector got swapped.
So if compression is good, and you have ignition, and it's isolated to cyl 2 only I would say its on the control side of the injector. Now you may have reinstalled the injector back to number 2 (*it's a 25% chance, much better odds than vegas)
I would say ohm out the injectors.
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Got you a bit of love from my data source provided. Happy hunting
 

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Have you tried swapping that spark plug to a different cylinder to see if it follows? You mentioned swapping the injectors, but never the plug. Or just changing the plug altogether. Sometimes a plug works well enough to ignite in high cylinder pressure scenarios like when you rev it as you mentioned, but at idle it's not putting out enough spark to actually ignite the fuel/air mix.

I have an 03 CBR600rr that had a similar issue a lil while back. At idle and low RPM it would spit and sputter on one cylinder only, but as soon as you revved it or put a significant load on it it would run just fine. Changed out the plugs and the problem went away and hasn't come back since.
 

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Discussion Starter · #8 ·
Have you tried swapping that spark plug to a different cylinder to see if it follows? You mentioned swapping the injectors, but never the plug. Or just changing the plug altogether. Sometimes a plug works well enough to ignite in high cylinder pressure scenarios like when you rev it as you mentioned, but at idle it's not putting out enough spark to actually ignite the fuel/air mix.

I have an 03 CBR600rr that had a similar issue a lil while back. At idle and low RPM it would spit and sputter on one cylinder only, but as soon as you revved it or put a significant load on it it would run just fine. Changed out the plugs and the problem went away and hasn't come back since.
Yes I put new plugs nothing changed. I switched the coils out but still cylinder 2. This weekend I finally have time to check it out. So I'm going to look for more vacuum leaks. Also I'm gonna check the valve train. I've read a flattened or scored cam can give those symptoms.
 

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Discussion Starter · #9 ·
Ok so I checked:
Vacuum leaks - none
Injector wiring to ecu - good
Also did a wiggle test at ecu engine harness connection - good
Injector spray pattern - good
Cleaned injectors
Spark and switched coils - good
Compression check - 175psi
I have P0302 cylinder w misfire
Shakes at idle, low power and check engine light flashes when accelerating. At a higher rpm but cruising gets better.
These are my cylinder 2 cam lobes. How do they look to you guys?

Pictures are intake cam lobes first then exhaust. Timing chain still in time. Cylinder 1 TDC, timing Mark up, and cam sensor lined up with Mark.
Circuit component Fluid Wood Liquid Audio equipment
Office equipment Red Gas Auto part Machine
Product Bicycle part Gear Wood Automotive wheel system
 

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Mambeau / Admin
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Did you check the compression on all 4 cylinders?

Your #2 cylinder seems to be fine.

The factory specs are:

178 psi (designed; factory; new) per cylinder
Minimum acceptable = 127 psi
Max difference between any 2 cylinders = 14 psi

It's odd and rare, but it's possible for out-of-range compression on one cylinder to throw things off enough to cause what appears to be a misfire in another cylinder.
 

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Discussion Starter · #12 ·
I checked compression on the other cylinders they were all 175psi. Im just gonna do a rebuild. I have my suspicions that one of the valves isn't seating 100%. It seems I don't NEED one but I'm hoping I'll find the reason why it's misfiring. Plus I gotta do my timing chain and my front seal. I'll post after I finish for the final verdict of what the culprit was haha. Thanks for your help guys. I do have a few questions though...

What is a good rebuild kit to get? I already have a timing kit the guy I bought the truck from gave me. I believe it has a water pump as well.

What is a decent stainless header? My exhaust manifold has a small crack near the collector. I figured I'm going to spruce the engine bay up a bit and I think a nice stainless manifold would look good.

Im also going to do a egr delete. LC engineering website says they have no products due to covid and back orders. Does any other brand have decent egr kit?
 

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Mambeau / Admin
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I don't have any specific tips or recommendations on the rebuild kit, header or egr delete kit.
 

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Where is the crack exactly?
You said on the collector...
Working a hunch here.

Other thought would be to measure the cam lobes for #2 and do a leak down test
 

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Discussion Starter · #15 ·
Where is the crack exactly?
You said on the collector...
Working a hunch here.

Other thought would be to measure the cam lobes for #2 and do a leak down test
I don't have any specific tips or recommendations on the rebuild kit, header or egr delete kit.

The small crack ( about 1 1/2") is in between cylinder 1+2 collector and cylinder 3+4 collector. I don't have a leak down tester. But I did wait a long time during the compression test to check for a pressure drop but didn't really drop.

So the other day I decided to start taking the intake manifold off to see if the intake gaskets had a hidden break on them and also to replace the fuel filter. Then I was gonna put it back together to see how it ran. This is what I found...
Automotive tire Motor vehicle Gas Rim Automotive exterior
Automotive tire Gas Snout Rim Circle


Upper intake
Automotive tire Vehicle Automotive exhaust Rim Bicycle part
Automotive tire Liquid Audio equipment Gas Circle


Lower intake
Photograph Vision care Eyewear Motor vehicle Automotive exhaust
Hand Automotive tire Tire Wheel Crankset


Head intake ports
Motor vehicle Automotive air manifold Gas Auto part Nut


And PCV port on intake manifold
Rim Automotive wheel system Gas Household hardware Metal


I'm guessing the pcv decided to off its self and the motor was taking in oil. While simultaneously mixing that oil/air mixture with the egr gasses making all this build up. Now, it's pretty bad but, I still don't think this is the reason why I ONLY cylinder 2 is misfiring.

Anyways, new plan of attack now. Seeing as how I have really good and EVEN compression, my new plan is:
1. Try to brush this gunk out of the head and use a vacuum to collect what I can.
2. Clean the intake and the valve cover out with the solvents I use at work.
3. Replace the PCV and check the valve lash.
4. I purchased LCEngineering EGR delete kit. I might wait until after I find the reason for the misfire before I install it because if the egr was leaking exhaust gas all the time I'd probably get an egr code.
5. Replace the intake gaskets and the fuel filter.
6. Put everything back together.

Then I'll see how it runs. If I still have an issue then I'm going to replace all the vacuum lines. Then spark plug wires, then coils. If still an issue I'll pull the head and inspect it then go from there.

It's hard to come up with a plan of attack when I don't know where to start anymore. But I'd be upset if I spend $1,000 on rebuilding the motor just for it to still misfire.
 

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That's pretty typical of any engine with a PCV system. Hell, my 2019 looked about half as bad as that when I pulled it apart at 12000 miles to install the Magnuson s/c. A catch can is the best answer to that. I have one on my 2000 turbo reg cab and it works great.
 

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Discussion Starter · #17 ·
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So brought the intake manifolds to my work and ran our solvents through them. But the layer was so thick and hard, I would have had to leave them in there with the pumps running for a week to get rid of this build up. Let me say I'm glad sand blasters are a thing.
Tire Wheel Automotive tire Tread Synthetic rubber
Automotive tire Alloy wheel Crankset Rim Bicycle part
Automotive tire Serveware Gas Automotive wheel system Circle
Automotive tire Motor vehicle Automotive design Automotive exterior Engineering


As for the intake ports, I didn't really want to take the engine apart, so I used a vacuum and a wire brush to get the build up on the head. It just so happened that my vacuum hose tip and the wire brush was the exact size as the head ports. I was able to get most of it out. I also did the fuel filter while I was in there.
Motor vehicle Automotive exterior Gas Auto part Engineering
Light Automotive tire Composite material Building material Auto part


Put it all back together with the LCENGINEERING egr delete and new silicone vacuum hoses.
Automotive tire Hood Automotive lighting Motor vehicle Steering part
Gas Tints and shades Auto part Wrinkle Personal protective equipment


Fired it up and...

Same issue. Misfire still there. So I figured at this point I've tested everything and it all checks out. Time to start throwing parts at it. I was leaning more to a spark issue due to the misfire being predominantly during acceleration. I already did the spark plugs, so next was the spark plug wires...

THIS WHOLE TIME THE ISSUE WAS THE SPARK PLUG WIRE FOR CYLINDER 2!!! I put new wires on it turned it on, then boom, perfect. I was trying to do it the right way and check everything correctly and find the issue that way. But I guess sometimes you have to throw parts at it. Haha. I checked the wire with my ohm meter and it checks out fine. No break in them, the resistance was fine, no corrosion, no oil and spark for sure passes through it. I think what was happening was the clip for the spark plug or the coil wasn't a true connection.

Thanks for your guys' help. Much appreciated. Let me know what you guys think. Any ways here's a picture of the engine bay.
Car Vehicle Hood Motor vehicle Automotive design
 

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Mambeau / Admin
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Glad to learn you finally found the source of the misfire problem. Sorry to learn you put in a lot of effort that wasn't necessary, but ...

The silver lining is a spiffy upgraded engine bay!
 

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👍🏻 I had my students doing some testing (I teach Automotive tech) and found some wear issues and a toyota logo fuel filter so I ordered a new round of tune up. Runnin ok but like 1/2 the tip of the rotor was gone so rockauto.com boom. Putting a new pcv and grommet cuz it's bricks.
 
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