i just bought a 97 cobra has 87k with cold air intake dialblo sport chip and flowmaster h pipe and exhaust when i hit high rpms and then let of the gas then hit it again it will backfire or doing fast shifts it will back fire soon as i depress the clutch. please help i appricate your help
cobra backfire ?????
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cold96snake
Dirt-Old 20+Year Member
cold96snake
Dirt-Old 20+Year Member
99% sure it's you're mail order tune and an exhaust leak. Pull the chip, unlpug the batt first for 20 min.'s at least, and get under there to tighten that exhaust up.
That should reset the pcm.
That should reset the pcm.
I did all that went as far as just leaving the chip out still had a backfire pissed me off do you any more suggestions i appericate all your help only will do it if i slam out on the clutch if i slip the clutch at like 7rpm it wont do it or just delay the shift. and the car wont miss a beat when im driving it only on shifts the other day i whipped like 3 dounts and was playing with the gas so it wouldnt red line every time i would wipe around and let off the gas then hit it again on the turn it would backfire
cold96snake
Dirt-Old 20+Year Member
well, it could be bad o2 sensors, but you'd probably have a CEL. I don't think it's hurting anything, but you're probably running rich. It's just one of those things o/r h-pipes do.
ljinx23
New Member
actually, my car does the same thing. I think it is a fairly common occurance, and shouldn't be anything to worry about. do a search on svtperformance.com
EPIK
Member
My 03 Mach does the same thing, but only on quick shifts & usually between 1st & 2nd. Im not sure what causes it because my motor only has 39k & is basically stock besides a C&L 85mm, MRT Catted H pipe, & Bassani catback. I cant remember if it did it when the car was stock. I think its a 4v thing.
Slowbra_12
New Member
I don't think you answered the check engine light question unless I overlooked it. Take it to AutoZone if there is one in you area. They will do a check engine diagnostic (FOR FREE) and can tell you what the problem may be. Just tell them the check engine light is on whether or not it is, and see what pops up. I blew a vacuum line off my car (and got the check engine reset, which came back on the next day)and took it there and they said it most likely was the vacuum line. However, the free diagnostic did raise a few eyebrows of possible reasons such as O2 sensors and catalytic convertors. May be worth checking out.
BennyBlown2v
New Member
Yeah, autozone FTW! I took my daily driver Honda car by a NAPA auto & truck care center cuz it was closer than autozone, and I buy alot from the NAPA parts next door, so I go in and ask to get the codes ran for free. The guy at the desk is like "alright then lemme get u a service guy" so he comes out, is like "yeah just fillout this form" and I'm like "well I just want the codes checked, it has a CEL, ok?" and he responds with "no problem no problem, we just need some info for our records." Before I even start I ask again just to make sure "so theres no cost to get the codes checked right?" and this joker is like "It's an introductory fee of $83.65, but then if we find any codes we'll tell you what each one means, and what might be wrong!" ...acting like that was a big accomplishment! So long story short, drove a bit farther to AutoZone, got the code worked out, drained/filled transmission, good as new
I would figure your backfire is coming from an extreme rich condition, and/or an ignition problem (have your coilpacks tested, and replace the wires if they are old).
I put a new xpipe and new mufflers on the car it took care of back fire think it was just the flowmaster system i had thanks for all the help.
blackfang
Founding Member
Not really. All they will do is pull the code and tell you what parts to buy. That is what we call a parts changer, not diagnosing the vehicle. They won't fully test and diagnose the system, just give you some guesses. Also if there are no codes stored or in there, they can't do anything. Sometimes you can get parts that fail, but not necessarily set a CEL.
hotcobra03
Active Member
My 03 would then the valve blew.valvetrain tic sounds like exhaust leak . Try doing a compression and leakdown test
Back-fire could be a few things, most ignition related than anything, plug wires, coil, do you have any codes (engine light) on. Many people need to get away from these canned tunes, example I had a customer come in with a 96 he had a blower installed on, he wanted us to tune it. After data logging the car, it was out of fuel, out of spark and the maf pegged yet it ran okay, there is a example of a car if the customer would have made a pass on his mail tune, boom he would have needed a shovel to clean up the mess, however in your case it sounds like a mechanical issue not tune related but more ignition related.
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