What could cause a enging miss ranging from 1500 RPM to 2000 RPM? I just got finished installing vette heads and headers, still using stock PROM. Does the stock PROM have a too weak of a fuel curve for this setup? OR could it be the EGR, because the heads don't have egr ports? Any other ideas???

 

Oh yeah...it's a 88 L98 Camaro.

 

Does the miss occur when you're at part throttle after warm-up? If so then it's not the fuel curve since you're running closed loop via O2 sensor feedback at that point.

Disabling the EGR does affect the timing needs of the engine. Try backing down the initial timing at the distributor by 4 degrees and retest to see if the miss is still present. If yes take out another 2 degrees and repeat.

If the miss goes away after retarding the timing 4-6 degs then you need to take some timing out of the spark advance tables in the PROM. If you still have the miss look somewhere else for a problem.

 

It's the heads themselves.
There is another thread going and I just posted about them there.

You'll just be running in circles till ya get burning proms. There are no mechanical only fixes for what you have.

Read up on where ever you see ARAP

 

Thanks for the help guys... I plan on burning a chip as soon as I get the equipment together, plus get or build a scanner. I did increase the TPS to trick the computer to increase the fuel, I still think it leans out in the lower RPMS. I also increase the timing to around 12 degrees which made the idle smoother, so you think I should change the timing to 4 degrees?

 

If you've been running 12 deg intial then just returning to the stock 6 deg setting should eliminate your low speed miss. Once you get into PROM burning you can really get total control from idle through redline.