Did you pull the spark plug wires and look to see if they are covered in oil or water>?
Its comon for those to leak oil or water into the spark plug chamber causing a miss-fire?
Let me know...
Man you did the code read by grounding the two terminals and it did not flash?
You put a jumper wire between two terminals of the diagnose connector and (turn the key on) right?
Hmmm, yes unfortunately its a limited function (old school) system... Ok we will try plug wires and go from there if the vehicles is at idle and you gently rev the accelerator by hand it will shudder a little which indicates bad secondary ignition IE plug wires.
Honestly I would replace the OXUGEN SEnsor if its never been replaced, its considered maint. and they only last like 60k miles. Maybe also remove the spark plugs and verify the (gap) is ok just in case one was dropped and it was flattened a little.
I just got my new spark plug cables installed. This did not help.------
To give you a little more info, I just bought this vehicle and am trying to fix it up. It seems in decent shape considering the age. It does have the exhaust hanging loose form it just behind the catylatic converter. Do you suppose this is affecting some needed back pressure to allow the emissions system to work properly? This is just athought I have had. I am getting the exhasut fixed tommorrow.
Yes exhaust back pressure is critcal in relation to some sensors working properly etc.
At least you understand trying to answer questions without physicaly touching the vehicle is difficult at best due to so many unkowns. We basicly replaced components that are considered maint. anyway and def wont hurt the perfomance.
Also ask the shop if they can attempt to read the codes for you...