302 trick flow heads trick flow cam holley systemax intake homemade turbo kit mpt70 42lb injectors pmas meter no tune. Car has been running great lately, than this. Out driving around and the lower radiator hose bursted. Temp. never got above 270 before i shut it down. Now the car is breaking up bad at steady rpms and 1/4 throttle acceleration. can hear it popping through the exhaust. If i clear it out it runs alright till i slowly accelerate again. Afr looks fine. Two wires were burnt, changed them and the plugs that didn't help. Put stock coil and disconnected my ignition box. No change.

 

How do the plugs look? any coolant in the oil? No tune is prob not helping your cause. You say afr's were good, what are they when?

 

Afr is around 14.7 and it doesnt jump around when its popping. The car ran fine before with no tune. It was davids featured car this month. bought it off him a few months ago and drove it every day til this. Plugs looked alright. I used octane booster the last tank so they were a rusty brown color. I thought I fried an o2 sensor but it does it upon first start up too.

 

i cant believe that the afr would not jump around with the car running badly like that.

 

when its at a steady rpm. say 3000 it goes from 14.8 to 15.2 at the worst. fuel pressure stays constant too. All the gauges look fine, it just has a pop coming from the exhaust and the rpms will try to jump around a little as it clears up.

 

Lots of things to check. Compression, plug wires, connections, and even plugs wouldn't hurt. Pop the distributor cap off and you will see the little pick-up that contacts with the rotor...make sure it is tight and dont wiggle. Or if you have another dizzy try it. You could have barely popped a head gasket but cant really see the side effects accept for the slight miss.

 

Did a compression test today and it read 120 all the way across. Checked the cap and rotor that was fine. Took her out for some full throttle passes and it ran great. Still has the hiccup at low acceleration and steady rpms. Ordered my new plug wires to see if that helps.

 

What ignition are you running and where is it located?

 

I'm running the crane hi 6 with timing retard. Its mounted in the engine compartment. This isn't the problem though cause if I disconnect it and hook it up to stock ignition it still does it.