Car started to back fire when i let off the gas then at stop lights the rpms where droping like the car wanted to Stall. Any ideas would be great thanks Tim

 

My 1989 GTA 350 TPI did the same thing a month ago. It would backfire, RMP is all over the place and felt like it was running on 4 cylinder. After some research, it was suggested that my coolant temperature sensor could be bad. Sure enough the problem was fixed once replaced.

 

wheres your coolant temp sensor? my secondary one on the block is broken and when it gets hot I flick a swicht to turn it on, but my primary seems to always be on and I got a performance resource chip. Now that you mention it the rpm's only jump around when the car temp is over 190

 

Per pic

 

that would be worth a shot. another thing to look into would be the tps sensor. any codes?

 

no codes check engine light hasn't come on.

 

the motor could of jumpped timeing

 

Mine backfires all the time... but that's with open headers

Might be an exhaist leak? I'm sure you'd know that it it was though... running to rich?

 

you might pull the timing cover and check the chain slack...should not be more than .500 inch

 

ok found out that the fuel is ignighting in the tail pipe on the down shift and throttle, but not all the time. would this mean timing is a little out?