I have a 1991 R/T Stealth Twin Turbo. 3 years ago I took it out of storage and it started backfiring, totally undriveable. I made the mistake of leaving the same gas in it for two years, one of those years it was never driven. The first thing I did was check the gas, it looked somewhat yellow so I drained it and put fresh gas in it but to no avail. When I started it up it still backfired like crazy. I took it out for a drive and it really misses and backfires, so much so I was afraid I was going to blow something off. So, I have changed the gas filter, plugs, wires, and had the injectors cleaned (they weren't dirty) but it is still backfiring. I have ran electrical checks on the coils and PTU per Stealth316 instructions and they appear to be ok. Recently there is a new nose that sounds like it is coming from inside the dash when it is ran at higher RPM's, it's the oddest sound, like you would expect if something broke and was slapping around inside the dash?????
I pulled a couple of the plugs and they are pretty carboned up.
I'm at a loss and any help and suggestions on where to go next will be greatly appreciated.

Thanks,

Jack

 

Seeing that these do have a timing belt, I would check to see if it jumped a tooth or 2. It's always a possibility.

 

Thanks William, I will look into that.

Jack

 

The problem you describe is one of the symptoms of an ECM going bad. Mine (92 RT TT) wouldn't fire cyclinders 3 and 6. No power, back fire because of the fuel buildup in the exhaust, and really rough at idle and high rpm. If you have never had the ECM repaired than this is more than likely your problem. I found a place in Florida that can rebuild these for $200 flat rate, or sell a reconditioned unit for little more than that. 5 day turn around time and a 12 / 12 warranty. Let me know if you are interested and I can give you the information I have.