I have a problem with my car and I was wondering if you could help me out. I have basically exhausted all that I know about the car and I really need some help before I push it into a lake. Just kidding, I really like this car. When it runs, it runs great. Just to remind you, it is a 1995 Firebird Formula LT1. This is what happened before I worked on it that I already asked you about.

BEFORE: When you first start it up or clear the codes with a scanner, it runs fine. Then a couple minutes into it, when you go above 3,000 rpms, the car looses tons of performance and keeps on making a backfiring /misfiring type noise. This is without the supercharger system installed. I want to fix this problem before I install it. The codes that it sets off are the following: Service engine soon, low oil, ABS INOP and that is about it.

AFTER: Brand new parts - Optispark, Water Pump, 02 Sensors, 8.5mm MSD Plug Wires, Starter (bought brand new one for a good deal a year ago-nothing to do with problem), Coil, Thermostat. I got in the car and it started right up. I reved it up it cut out at 4-5 Grand. I went ahead and took it for a test drive. It ran a little rough, but not too bad at lower RPMS. Then I just decided to go for the gold and leaned into the throttle. All of the sudden the car hesitated really badly and made the biggest backfire I have ever heard and the engine shut off. I let out on the clutch while it was moving (Engine off) out of habit and it backfired again very loudly. Now every time you try to start it, it just keeps on cranking and sometimes it starts. When it does start though, if you give it gas it backfires loudly and within 2-3 seconds, regardless if you give it gas, the RPMs slowly go down until the car diesels and shuts off. I am pretty mad about the whole thing because I have spent almost $1,000 already on the repairs and I really want the supercharger install to begin. I agree with what you told me about the optispark and changed it with other necessary parts. I have scanned it with a Snap-On Diagnostic kit from my friend’s dad and can’t make any sense out of the codes (the codes that do get set don’t really have anything to do with performance). I don’t know what the code of 40K pulses per cycle error means. Any advice would be helpful because I don’t really have a car right now.

 

Make sure you didnt hook your spark plug wires up wrong, just something you might want to double check. Wish I had more idea, dont worry though somone will fix you up. Sorry to hear about it and good luck.

 

Blower install? Start saving for the Rebuild now.