I am working on a 91 deville with a misfire & will chugg when going down the road. There are no codes. I have replaced the plugs, the fuel (pressure was 30psi & fell off on accelleration), cleaned the throttle body. I am now stumped. The car had a waterpump replaced a week before being brought to me for this problem. I do not think that the water replacement has anything to do with the current problem.
I have not checked timing or performed a cylinder leak down test... I will say that after the tune up & fuel pump it took 15 miles of driving to have the problem resurface.

I am thinking that there maybe a problem with the TPS, but no code???

Any suggestions will be greatly apprecieted.

 

What did fuel pressure fall to?

 

Possibly a damaged spark plug wire. Can you scope it to check secondary ignition? A faulty plug wire or cracked spark plug usually wont set a code.

 

I assume the fuel pump was replaced. What is the fuel pressure NOW?
which of the two problems resurfaced? miss or chug along?
have you pulled the fuel filter? that probably wont fix the misfire, but maybe address the chug along issue.
is the car SMOKING?

.

 

I have removed the throttle body & EGR, cleaned them problem still persists. I have installed new plugs, the wires are good. It is giving me an E96 code, torque convertor over stress. I am going to try and disconnect the torque convertor and see how it goes.

 

it would fall to 26 psi

 

plugs & wires are good