m-m-m-miss

[svohoo]

I have a similar miss to TurboJoe's, but mine only does it in the afternoon when it's hot (at least 85-90 deg), not in the morning when it's cool out. It also only does it from about 2600 to 3000 rpm's, and only at very light throttle, just enough to make the stock boost gauge go to about 6 or 7 psi. I just finished cleaning up from the common PCV issue (cleaned hoses, IC, and plugs) and I'm pretty sure all clamps are tight.

[svobud]

Have you run a KOER code check yet? That would be where I would start - next would be the TFI. When they start going bad, it's usually a HEAT related failure. Next would be to check the voltage on your TPS....

[svohoo]

Thanks, Bud. I should have thought to do a code test first. I'll give it a try when I get home.

[svono50]

David,

From the conditions you are seeing the miss, that is right about where you get a large advance on the timing by the EEC to get things going. Combine this with some boost and you could be getting some knocking/pre-ignition. The miss may be your knock sensor working by pulling out the timing. If it is your TFI and/or your PIP modules then you would experience it worse in higher rpm/boost situations (ask me how I know).

As your engine heats up it becomes more prone to knock/pre-ignition. A couple ways to test this is to get better gas (if possible), back off your initial timing to 6-8 deg or gap your plugs slightly tighter (0.028-0.030) and road test under the conditions where you experience the miss to see if it is either gone or reduced.

Like Bud said, start with the codes and work your way from there. Let us know what you find.