Hi all I have a 92 3.1 MPFI firebird and it is not running right at all. We have no clue whats going on but it misfires really bad, and has major carbon build up. I cleaned the spark plugs spotless put them back in and it ran fine for about 5 min. before it started craping out again. Pulled them out again and they were black as pitch. So its running to rich, i know that but not how to fix it. The check engine light is on but when I cleaned the plugs it went off until it started misfiring again. We read the codes, and it came up 12, 33, 43. 12 is no distributer reference pulse, 33 is map sensor signal to high and 43 is electronic spark control failure. We narrowed the ESC failure down to the knock sensor. Looked at it and the wire leading to it was disconnected and destroyed. Re connected it and now it will run at a high RPM when started and go low and start to misfire and idle horribly. SO i have no idea what is going on there and i don't know what it means about no distributer refrence pulse, or about the map sensor. If you could give me some advice on how to fix my car so it will run right that would be great. thank you.

 

any help would be great.

 

Do you have the GM service manual for your car? If not I would recomend you get one and I'm not talking about Chiltons, I mean the actual Pontiac service manual. There are a series of tests to be carried out using flow charts that will narrow your problem down as you have to many codes to start shotgun troubleshooting. You could very well have a failed ESC unit. I had it myself. It was a ground wire to a relay. You need to go through the different systems and check them individually. The service manual will have diagnostic testing for each code. You will need a Multi Meter. I really don't see away around this. Theres no way anyone here will be able to guess whats going on.

 

Thank you, i do have the general motors engine managment systems book. I have it at toyota were my dad works and the guys there are great with what they do. He is a salesmen but give him any carburated car and he will have it runing in no time. Thanks for the tips i will have to pinpoint the areas to check and then use the multi meter to check it, i dont have one that reads charts but it will tell me voltage, and in the book it tells you what voltage you need, thakns again.