My Trans Am started running like crap a few weeks ago. It backfires at all accelerations and idles fairly poorly, but rarely dies. I brought it in to my school (I have a high school auto mech class) and have been attempting numerous things at my instructor's guidance. The Trans Am had a rebuilt mechanical Quadrijet carburator put in a few years ago, so the computer does nothing for the car. I've replaced spark plugs and checked compression and all that's fine. Next my instructor is telling me to check for looseness in the timing chain, but does anyone have any better ideas?

 

Cheak the cam for flat lobe's

 

Probably a dumb question, but did you check the timing? If so was it close to where it should be? If not, and setting it to where it should be make any change in how it run?

It might help for some more info (mileage on engine, changes other than carb) to help diagnose.

 

The Carb is Mechanical, but is the Distributor still HEI? If you're running a Non-Computer Carb, you should be running a Vacuum Advance Distributor.

 

Okay, sorry, It has 140k miles on it. And what does HEI mean? my excuse is I'm only 17 and this is my first firebird... I don't think it's flat lobes, it happened fairly suddenly on my way to school one day. I did check the timing, but it wasn't that far off. All help is appreciated!

 

High Engergy Ignition