backfire....

[ahank1]

I have notice my car has been acting a little different. like when the rpms are coming down it will backfire. and when I accelerate it will hesitate once in a while. but the back fire mostly only happens when I shift from 2 to 3. I have no clue what the prob might be... and my service light has never turned on. is there any way some one might have been able to disconnect the service light.... can you still get your car scanned if it is not on.. thanks in advance

[Camaro Dom]

Re: backfire....

you COULD take out the bulb (or LED or w/e it is) and still scan the codes cuz they're stored in the PCM, i dont see why anyone would wanna tho... the best way to check is when you put the key in the ignition, the SES light should shine for a good 3-4 seconds right when you start up along with a bunch of other lights.

Quoth the haynes manual:
Engine backfires:
1. EGR system not functioning properly.
2. Ignition timing incorrect.
3. Vacuum leak.
4. Damaged valve springs or sticking valves.

I'll put my money on the vacuum leak first then the EGR. low probablility that the other two are whats causing it...

get your codes scanned first thing. then do a vacuum test.

[ahank1]

Re: backfire....

what about the hesitation at the higher rpms. do you know what might cause that... by the way thanks for the help

[Camaro Dom]

Re: backfire....

hey no prob man
again quoting haynes:
Hesitation or stumble during acceleration
1. ignition timing incorrect
2. ignition system not working correctly,
3. dirty/clogged injectors
4. low fuel pressure.

i dont know exactly what they mean by incorrect timing. the manual covers teh v8 models too and the LT1 has a distributor so that might be what they're referring to as far as ignition timing goes... again, i'd say start out scanning codes and then try to find your way from there.
EDIT: keep in mind that this is just a general runthrough of common causes. Obviously its by no means the end-all-be-all diagnosis guide.

[ahank1]

Re: backfire....

i heard that if your ses light is not on it will not read any codes or something like that

[Camaro Dom]

Re: backfire....

its free to try... why not?