For a week now I've had problems. I've spent a week searching the variations of what I listed above. I'm misfiring after warmup and around 3000 rpm, sometimes when I take off in 1st gear it craps out and then picks up again. I have new MSD 8.5's none are burnt or arching even under WOT or under load. Has a 2 month old OPTI, new AC Delco plugs, checked all the vacuum lines, checked the EGR while running the valve moves back and forth fine, if you push it in the car sputters and tries to die so I'm assuming that means it's not carboned up inside the intake, checked pcv valve, cleaned MAF with electronic cleaner (wasn't dirty), cleaned Throttle Body (wasn't bad). So that's pretty much all I've checked. It is also backfiring in between shifts and running super rich. It is not misfiring like it done when I burned a brand new MSD #5 on the primary header, that was very distinct, this sounds like it idles smooth even after warm, until I get it under a load it sputters and splats backfires, etc. In Open Loop (on startup) it does the exact same symptons as in (Closed Loop) after warmup. Oh yeah, checked fuel pressure with a guage on the road at idle, under load, and extreme load. Holds 42 psi and at idle about 36psi which is the nominal -8psi (normal with vacuum at idle). Manual calls for 41-47 psi. I do not think it's my fuel pump therefore. Fuel filter is brand new.

Any help is appreciated.

 

ttt

 

Check your oxygen sensors if you haven't already. Sounds similiar to my experience when mine were on their way out.

Derek

 

well how do you check them? The Bosch are not too expensive about 30 bucks, but is there a way to test them?

 

If it's doing the same thing right after startup (open loop) then it can't be your O2 sensors.

I'd suggest checking your plugs. Make sure none are loose (I had some loose ones a couple days after I changed mine).

If you replaced them before you replaced the wires, they may have fouled out and need replaced again.

 

maybe the maf?

 

I'll pull the plugs tomorrow and recheck them. I've had one work itself loose and actually crack before. The MAF is fine, I even cleaned it with electronic cleaner. I have an old Taylor 8mm on my #5 plug from burning the new MSD 8.5mm when I installed the longtubes but I doubt it's fouled. All my wires are clear of the headers. I'm at the point of disgust but I'm trying to keep my patience with this thing. It doesn't run like a fouled plug or bad wire but then again who knows, it could be a plug/wire condition that's not quite up to standard and running just ok. Thanks for the tips.

 

Have you tested the coil?

 

yup, it tests to 7.1 ohms on all points. Stockers usually test out about 8.5ohms. This one is stock and aftermarket units usually test lower so it's not the coil.

 

Your other ignition-related piece would be the ICM, on the front of the driver's side head. I've seen people on here describe similar symptoms before replacing theirs.

 

friend at Autozone loaned me a brand new ICM, not the problem at all. It's the same running from startup to nominal operating temperature around 3-4k rpm it stumbles and picks back up. Bound to be someone with the same problem. Again I have new wires, new plugs, new Opti (changed unrelated to this problem), tested coil (fine), no vacuum leaks, EGR is fine, cleaned and inspected Throttle Body (fine) MAF is fine, no burnt wires or anything laying on headers.

Open to suggestions other than what was already suggested on this thread.

 

ttt....need help here still.....please read the post before suggesting the basic stuff...done all that already.

 

Before you do anything check the wires. Make sure you put them in correctly. I had the same problem and my wires were switched. I took them out and install them again to the right connectors and the problem was solved.