i have a 1989 trans am gta. it has a 350 tpi. my problem is when i first start it up it runs just fine. but after 20 minutes or so of driving it starts running really bad. when i give it gas it studders really bad almost like it is cutting out. so i changed the plugs, wires, cap and rotor, and i also ran fuel injector cleaner through it. i ran fine afterwards for about a day and now it is running like s*** again. when i changed the plugs it was also very lean too. any help figuring out this problem would be very helpfull, and appreciative. thanks for the help

 

Flashing a code? When was the last time your o2 sensor was replaced?

 

sounds like its having trouble when it goes into closed loop, Try pulling codes and see what its saying. It sounds to me though that your O2 sensor ight be dead, I also had a MAF problem act the same way but the check engine light came on with that so I knew where to look.

 

the engine light has never cam on. i'm new at this so bear with me but how do i check the codes without having to take it to the shop

 

you can check the codes by jumping the upper two right hand terminals of the ALDL. it will flash a code at you through your check engine light. it will blink a code 12 at you, to read it just count the blinks, it will start off with one pause and blink twice and pause again, thats a code 12 which is normal. It will blink that code at you three times and then move on to the next one.

 

check the fuel preasure.

I never hear people recommend changing the timing chain. timing is the whole key to horsepower without it you can replace any sensor and get bad results