I have a pre-1986 gm crate motor that I put a speed density tpi intake on. I just got it running and i have been having troubles with it not running great. When i drive it it pops out the exhaust witch I think is being caused by a miss it doesn’t do it all the time only when it is under load. It doesn’t do it at all in Park/N. I have been troubleshooting it for a wile and the ECM isn’t giving me any codes and it has a new distributor, plugs and plug wires. What I’m thinking is it could be the cam not matching up with the ECM because I never changed it and it used to have a carb. I don’t know anything about the cam other then it is stock.

Could the cam be giving me problems?

 

i was having a problem like that not long ago in my 91 sd 305 tpi, under load on the highway it would lose power and "pop" on the exhust side but in park/n it woudl rev and be fine, just under load it would do this, turned out to be the igniton control in the dissy, be running fine since, might be worth pulling it out have having it checked at an auto store, they do it for free

 

Bad plug or plug wire? Just cause they're new doesn't mean they're good. Could have been dropped during shipping, at the parts store etc.