I have a 1983 firebird with basically stock 305. The only things i have done to it are headers accel in cap super coil and msd wires. When the car runs for awhile and gets warm it starts to buck a little and carry on. After I let the car sit for awhile it always starts right back up. I was thinking it was an ignition module breaking up and replaced it and it didn't help. Im not sure if it is starving for fuel or what but i dont understand why it would only do it when it gets hot unless it is vapor lock. Any help would be Appreciated Thanks.

 

Headers raise the engine compartment temps, so coils, wire connections, and all electronics get flacky.

Any codes? Can you scan it while it is bucking?

 

If it didn't do it before the electric parts swap out, put your old stuff back until you eliminate the cause.

 

I do not have any of the parts that were on the car before this is how the car came. I am thinking it is a fuel delivery problem maybe vapor lock becuase it only does it when it gets hot so maybe the fuel pump has a small hole in the diaphram thats making it act up. The problem is i cant check fuel pressure becuase it idles fine when it acts up and goes back to normal its only when it is moving. I am going to try to check codes while its doing it. I haven't checked them yet. Thanks alot for the help

 

Tee in a fitting between the pump and the carb and attach a temp fuel pressure guage to it. Tape it to the windshield.

Vapor lock will result in an immediate no run situation though. It will not cause poor performance. I'm assuming this is carbed?

In your history with the car has it ever run fine, did this behavior suddenly occur? Did you just get this car?

 

The car ran fine when i first bought it i did a full tuneup on the car and it sat for a good two months until i started driving it again. I started driving it again and I was at a stop light with alot of traffic so i had to wait awhile and i suddenly shut off, This was the first problem i had with the car. I tryed starting it again and it had nothing. I pushed it in a parking lot nearby thank god and let it sit for about an hour. I went back and it started right back up and ran fine until it got hot again and it's been doing it ever since.

 

This time of year should not vapor lock. How hot is hot? Does it crank and not fire or just not crank over (starter solenoid)? The pickup coil in dizzy would be another suspected part (crank and no start). A quick short shot of starting fluid would rule out fuel.

 

Are you sure your fan is operating? If its not, try turning on the a/c to see if the fan still works. If it turns on, then its probably a bad temperature fan switch. if its not then you have a wiring problem.

 

The fan is working and the car cranks over and starts right up. It's just when you get on the gas even the slightest bit. It runs at normal operating temp. it just breaks up when it gets warm.

 

What's your oil pressure doing when it starts to run funky?

 

Are you sure you didnt crack any spark plugs when you installed your headers? because i cracked three when i did my installation and it didnt miss until it warmed up either.

 

My oil pressure stays at 55 all day long even when it starts to act up. The headers were on my car when i bought it and i just recently replaced the plugs so they shouldnt be cracked.