91 tt Stealth
 

I got a 91 stealth Twin Turbo all wheel drive have done a tune-up mass air flow sensor change everything I can think of still can't get it to run right even after new plugs still says 3 and 6 misfire please help

Compression test.

Sttealth
 

It runs great for a few minutes has plenty of power thinking still a misfire on the coils not sure all new to this was my dream car but I'm frustrated

Are 3 and 6 on the same coil?

How old are the O2 sensors?

not sure the car sat for 16 years we got rid of all the bad gas changed fuel pump coils module spark plugs spark plug wires mass air flow sensor don't know what else to do injectors are working fine runs great at 3 Grande just when it's lower runs like crap

Ok, did some checking, 3 and 6 are indeed on the same coil. So, check electrical connector to the ignition module, make sure you are getting good connection there.

Stealth
 

Figured out this morning that it runs great if its cold then starts missing once it gets warm what kind of sensor could that be

Try unplugging the O2 sensor(s), and see if it runs better. (that WILL set some codes.) If that doesn't make a difference, might be a coolant temp sensor, intake air temp sensor, or any of a number of others that start to fail when they get warm. Doing some data logging would likely be enlightening. But, you would need a log that started with the engine cold, and went all the way thru warm-up, and lasted a bit after the problem presented itself.....