Pulling my hair out over a misfire issue.

[Piktureit]

Ok, I know from this forum that the 3.9 eats coil packs. I've been getting a misfire, stuttering, stalling and just basically crappy performance from my 2000 LS.

I've replaced the coils, plugs, tps, iac, cleaned the throttle body. I've got a check engine light but the place I had read the scanner for codes couldn't bring any up. The light flashes occasionally so I know it's gonna screw up the cats but I'm running out of ideas. I'm starting to fear an internal mechanical issue, (burned valve, etc.).

Does anyone have any ideas that I haven't tried? Thanks for your help!

 

[stugots]

Assuming you changed the coils correctly at the same time with the plugs gapped to spec, and all connectors are plugged in correctly, could be your timing. Have you replaced the tensioner? Could of skipped a tooth.

 

[joegr]

Do a compression and a leak down test.
Check fuel pressure.
Check fuel injectors.
Check PCM.

 

[md1twal3]

Maf?

 

[De-marko]

Yeah and check to make sure all injector electrical connections are plugged in tight. A couple years ago I ran into this on cylinder 6 and found the injector was disconnected just a bit.

 

[lincolnlogs]

check out my huge coil thread. (too lazy for a link)