On an 87 IROC 5.7 where is the ESC located and what are some symptoms of one failing?My car has a miss in it with the wire that you disconnect to set initial timing hooked up.But if you disconnect it,say to set the timing it idles perfectley smooth.plugs,wires,cap,rotor,ignition control module and coil have all been replaced.This freaking miss is driving me insane.

 

I'm having the same exact problem and I've changed the same things you have changed. The ESC module is on the drivers side firewall, furthest toward the engine and behind the MAF power control module....Tonight, after replacing the aftermarket prom with a stock prom, D/C the ECM...again and again finially got code 33 and 42.....MORE WILL BE REVEALED....

Stan

 

I've had that problem before. It's often a symptom of a bad magnetic pickup inside the distributor (how old is your distributor?) or the ECM itself can be going flaky. No, neither of these things will generall light the check engine light.

The location given for the ESC module, above, is correct.

 

ECM and distributor is new.....still no timing advance and code 33 & 42

Stan

 

Did you solve your problem? I still have mine. I found a few wires at the MAF that were not connected and or frayed. The grnd inside the distributor was not connected well. Now it will start with brn/blk wire plugged in but will only pulsate low to high idle. Try giving it just a little gas and it ???????????????????????/ pops????????????????????????????????????????????????????????????? I may put another distributor in just to see what happens. What do you think??????????

Stan