Ok I have a 94 Z28. Has low RPM stumble and a miss at high RPMs. I have done everthing except the opti. I have an opti on the way. I also should be recieving a MSD 6A soon. Let me know how this sounds.

-New opti
-New Wires
-NGK TR55 plugs
-MSD 6A

Also should I purchase a MSD blaster coil or something simular to go with the MSD? I want this to fix my problem and I want to do it right. The 1st time.

Thanks for your replies and information ---- Brad

 

what do you mean by every thing but opti? what have you checked or replaced?

 

ttt- AZ28

 

Do your opti first and see what the result is!

 

Did you replace the ICM and COIL already?

 

most of the time the high rpm miss is coilwire. the low stumble is opti.

did you change the coil wire.

 

Ok, fuel pressure is fine, new fuel filter, new MAP sensor, deleted air and egr, cleaned tb, cleaned tb sensors (AIC and forget the name of the other) seafoamed twice, cleaned MAF.

Haven't checked O2 sensors yet.

All this helped but still have stumble. -Brad

 

what did you clean the throttle position sensor with?

 

Carb Cleaner making sure not to get it in the electric part. There was a lot of carbon on it that I used a little piece of scotch brite to clean.

Today I added an MSD Blaster Coil and relocated my IAT to the hole on the stock intake right before the MAF. Also cleaned the MAF with carb cleaner.

---Brad

 

how is it running now?

 

Engine is a little smoother through all RPMs. Its just not as powerful as it should be IMO. I have a friend with a 95 Z28 and his is a lot faster than mine. We have about the same mods, I probably have more than him come to think of it. I hope once I get new wires, some decent plus and a new opti that I'll be cool. Then I can spend $ on important things like gears. -Brad

 

do you have access to an ignition analyzer, if so, you can see what the ignition is doing. if the engine feels like its running smooth but low on power, i have seen that be due to the opti-spark or weak valvesprings. you'll be able to see the difference on a chassis dyno.

 

Whats an ignition analyzer? Is there another name for it? My opti, msd 6a, plugs and wires are on the way so we'll see if that helps. Also as soon as I can afford to, I'm going to have my Dad p&p the heads, put larger valves in and get a cam, so I'll be getting new springs anyway. -Thanks-Brad