Random Misfire

redfirepearlgt

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So I have some hope I may have found the issue. I monitored the TP1 and TP2 voltage through the PCM to make sure it was a smooth ramp. Just sitting in the car with KOEO I could go though the sweep and listen to the throttle body open and close. I then had my wife start messing with the wires at the TPS and motor to see if it changed. Well it did. Specifically just wiggling the wires right at the TPS connector. You could hear the throttle plates open sporadically even though the throttle pedal was not moving. Got a new connector on order from Rockauto and hopefully that fixes it.

Good job. Intermittent issues are such a PITA to locate.
 

Saleen304

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Last update. The connector seems to have fixed it! I have driven a couple hundred miles with mixed driving and no misfires or any other codes. It even seems to pull a LOT harder up top than it did last year. Makes me excited to see how it does at the strip now since I was grabbing mid-10s last fall...
 

Saleen304

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Update: Car was running great without issues and then it started misfiring again on my final session at a road course. Long story short is I found what was probably my main issue all along. When I installed the harmonic balancer a couple years ago I must not have torqued it down enough which allowed the timing wheel to move and make some contact with my timing chain. This also messed up the keyed area on the timing wheel. Replaced the parts including timing components and she’s good to go.

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redfirepearlgt

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^^^ That would cause a misfire without a doubt. What led you to find that? It makes sense, but to factor that in on an issue that begins happening two years after the upgrade would make it more of an after thought than a likely probable fault.

Great stuff right there.
 

Saleen304

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^^^ That would cause a misfire without a doubt. What led you to find that? It makes sense, but to factor that in on an issue that begins happening two years after the upgrade would make it more of an after thought than a likely probable fault.

Great stuff right there.



I have been fighting this issue for more like 1.5 years. I am sure it just got worse over time. It was pretty lucky that I even found it. I thought I had a phaser issue so I replaced both phasers and installed limiters. During the process I screwed up the cam timing by a tooth so I had to pull the front cover off to re-time the engine.... and viola! Oh and I found the real issue to my phaser problem. Cut tensioner seal.

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redfirepearlgt

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The man above is shining on your parade with both of those finds. That gasket seal would cause an issue for sure. Reminds me of replacing internal optics on a 4000 watt CNC laser and suddenly having a vacuum leak test fail afterward from a cut O-ring that seals the mirror holder. It's the stupid little things that always seem to drive a person crazy.
 

bujeezus

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Man, I can't believe you finally resolved your issue. I woulda given up by now.
 

06monera96

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Glad you found the issue.

Thanks for the PCM (y) Canadian folks wants 400 bucks for it @_@..

BTW did the PCM have PATS in it?

I am able to start up the car and drive it without programming the keys weirdly lol
 

Saleen304

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Glad you found the issue.

Thanks for the PCM (y) Canadian folks wants 400 bucks for it @_@..

BTW did the PCM have PATS in it?

I am able to start up the car and drive it without programming the keys weirdly lol



Thanks. I believe it had PATS on it, but I had Lito send me a tune to disable the PATS during my tests. I returned it to stock before I sent it to you though.
 

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