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Random Misfires Cylinders 1-4

1699 Views 4 Replies 2 Participants Last post by  Big T
I first did the manifold tumbler flap actuator repair job and after reinstalling the manifold the engine ran extremely rough at idle and generated codes for random misfires on cylinders 1, 2, 3 and 4. I took it to my independent mechanic who said that when people attempt to repair the manifold, they typically come back with a misfiring engine because the tumblers are warped. He said that I needed a new manifold.

I purchased a new OEM manifold on-line and installed that. No change at all. It was suggested that I may not have seated the injectors properly and that I should install new seals. I purchased both lower and upper injector seals. I was able to find and replace the green seals which appear to be lower, but I have no idea where the black seals go.

I applied some engine oil to the seals and reinstall the injector rail. No difference whatsoever. Same codes for random misfires on cylinders 1-4.

I disconnected the harness plug from injector #2 on passenger side and noted a difference in the engine (hard to do as it's really running rough). Then I started disconnecting engine coils one-by-one while it was running. Really no discernible change on the passenger side, but when I got to the driver's side the engine dropped rpm when I disconnect the front and the second coil.

I'm told that the only real way to fight....err figure this out is to have it diagnose on the STAR system at a dealer. Independents don't have the STAR system and thus are generally left plugging in parts. Is this correct?

On the other hand, it would be much cheaper for me to plug in new coils with internet parts prices.

Where should I go from here?

Hate this car.
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First of all recheck everything, connectors, vacuum lines, sensors, etc, take them one by one. Exclude what could be an easy fix, sometimes you just forget a small detail which later ruins your day.
I redid this job following the advice to tie the gaskets in place with fishing line and that did the trick. When I pulled the manifold out, the gasket on the passenger side was completely askew running through the middle of #2 and #3 cylinders. On the drivers side the gasket was buckled on #5 . The pins intended to hold the gaskets in place don't work worth a damn. Tying them in place with fishing line through the bolt holes worked great. Once in place, cut the knot side of the line below the knot, pull the line out and insert bolt, one-by-one.
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Great job, I hope you love the car now ;)
These cars are better off leased for 3 to 5 years and turned in. Repairs are too expensive, especially if you take them into the dealer. We still plan to sell the car.
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