I have a 93 TA with the LT1, auto, car has 106k and runs a little bit rough. It also will not pass emmissions at idle the HCs are at like 450 and COs are at 1.1. I have replaced spark plugs, wires. and it helped some but still runs rough- next I installed a MSD 6a ignition box and it made the exaust smell a little cleaner, but still runs rough and dont pass emmissions. It seems to have a sporatic miss in the engine. At WOT the car runs very well and doesnt miss at all. Does this sound like a opti going out, or some kinda fuel problem?? I also replaced both 02 sensors. all parts replaced are GM parts. thanks in advance

 

Do anything to the coil or ignition module?I dont know anything about the MSD.Anywho,either those or the opti.

 

the problem was there before and after the msd install, I think coils usually fail worse at high rpm rather than idle.. any ideas??

 

Have the injectors professionally cleaned through the fuel rail. That's your main problem. Also clean or replace the EGR.

Be sure your air filter is clean when you go through inspection.

You should also run a can of cleaner through the tank at every oil change.

Be sure it is O2 safe.

Good luck

 

do these engines have EGR problems??

 

If the EGR is stuck open, it will run/idle rough.

 

it doesnt run real rough, but at idle the car shakes more than normal, and as you rev it up to 2500 rpms you can feel it miss a little but not real bad. the exaust smells like unburned fuel and gives me a headache, the MSD box helped a little but still smells like raw fuel.

 

could seafoam help him out at all you think? with the rough idle? i know it sure smoothed my idle out a bunch