Engine Shop Cant Find Misfire Problem

Does the car have cats? Any mods done?

Also, replace both o2's at the same time. If one was bad odds are the other isn't far behind it.

Stop throwing money at it and check the small stuff. Vac leaks, loose coil packs (bad boots will cause issues) etc.

kevlar said:

So far I've put new injectors in,new plugs,cleaned maff,new pcv valve,new o2 sensors on drivers side,fuel filter,fuel pump.Was throwing a p0413 code but has seemed to have cleared on its own shop says it's not there,but a couple lean codes have popped up,,I'm at my wits end an have no ideas left,,could use some help

Click to expand...

If you paid a professional to replace all of those parts without a fix, then my best advice is to get a new mechanic.

kevlar said:

T,heard that could cause a problem with a misfire,Could bad alternator diodes cause misfire?

Click to expand...

Yes it's POSSIBLE for a bad alternator diode to cause a misfire. However it's usually associated with a cam related DTC as well. But given how easy it is to test an alternator there's no excuse to guess.

Does this car have cats?

Are there any exhaust leaks?

Does this car use oil or coolant?

Have you inspected the front crank damper for run out and dry rot of the the ring damper? A loose or incorrectly torqued crank damper bolt can cause unstable timing. As well as cheaply made under drive pulleys.

Has a compression test been done?

In for result. I had a lean condition CEL, what it turned out to be was unmetered air through the cold air intake coupler. I had pushed the coupler to far in and it created some weird turbulence around the two couplers.

Sensitive little bugger, it was. Took me a while to figure such a silly mistake.