Ralls

iTrader: (32)

My car starts up fine and doesn't have any problems until it fully warms up. Then when it starts to sputter, and I give it more gas, it will backfire. Usually sputters when its shifted into 3rd or 4th and stays in gear when slowed down (30-45mph). Sometimes it will hesitate off the line driving normally too. At first I was thinking it was a air/fuel problem. But why would it happen only at warm-up. Also, it's progressively getting worse. All this started happening months after my header/exhaust install. My car has never stalled or failed to start up. Does any of this sound like the opti starting to go bad, or air/fuel ratio?

Cammd95Z

iTrader: (4)

my dads 94 formula had the SAME problem, after we put a new coil,opti, and plugs it died and we couldnt get it started, long story short we had it towed to dealer and it was the fuel pump! if you've got a fuel pressure tester id check the fuel pressure, you can buy one at advance or autozone for like 30 bucks. does it sound like its backfiring from the intake?? i was amazed that it was the fuel pump i was ready to tear it down and check timing...

Camaro94SS

i beleive i had to replace my opti and 02s at the same time....try one,then try the other, thats a general problem with these damn cars

Ralls

iTrader: (32)

Yes, it does backfire from the intake. It might be the fuel pump, which would explain why I loose some power when below 1/4 tank gas. It's probably clogged up with crap since I used to drive my car until it practically ran out of gas. If it needs a new fuel pump, how much money am I looking at?

Ralls

iTrader: (32)

Hey Cammd95Z, how many miles were on your dad's formula?

titter

iTrader: (5)

never starve a 4th gen fbody of fuel, especially the lt1's you are just asking for problems. they require fuel to keep themselfs cool ... no fuel, big problem. Right now Summit has a sale on the Granatelli fuel pumps for 90 bucks ... good deal. As far as it happening when the car warms up that is a symptom of the opti ... notice anything else? harder to start? rough idle? it is always a good idea to do a tuneup before going to the opti ... plugs, wires, fuel filter, and if it breaks up in higher rpm it could even be the coil. if everything has been changed recently sounds like it could be the opti.

Ralls

iTrader: (32)

Ok, my car has been well maintained before me. Mobil 1 since it was born, most likely never driven hard, and had 53K on the odometer.
My car starts up perfect. Idles fine too. The only time it seems to idle "bad", would be after the car has sputtered and backfired a few times, THEN it would idle at 500 rather than the normal 600rpm. The sputtering occurs from idle to around 3K rpm.
If I give it a little gas, and the needle doesn't move at all, does that mean a opti problem? cause sometimes on the highway, I give it gas and hear my car rev, but the needle and car won't move.
Lastly, I'm getting my car dyno tuned next week. Should I take it as is, or replace something first?