Ok looking for some suggestions. The problem that I'm having is its popping up through the intake. The engine won't even idle. Has no power. I have checked timing 4 times. Even pulled dist cap and pat eng. at tdc to make sure everything lines up. Thats all good. Also checked the plug wires are in the correct position(18436572). Thats all good and still having the same problem. So I proceeded to check valves and see if a push rod was bent or something. That checks out good. Didn't think a pushrod would bend considering they're molly push rods. So the next thing i did was check fuel filter. Checks good. Then tried putting in some gas treatment incase I got some bad gas and there might be some water in it. No dice. Now I'm at a dead end. Not sure where to look next. I'm pretty sure it's something to do with the fuel system because it's running pretty lean. O2 voltage is at .1 or so. This all happend in one day. Car ran perfect the night before and get in it the next morning runs like poop. Would appretiate any suggestions. Some info on my car its an 86 iroc with tpi., 24# injectors, head swap and cam swap. I have tts and pocket programer. Problems occur with factory chip and my mod chip.
Thanks For Your Time
Jason

 

Timing is off, back firing thru intake is a sure sign.

 

Could be CAM timing though. Did you recently swap the cam / timing chain set?

 

Yeah I changed the cam when I rebuilt the motor a year ago. I checked that as well as the timing. They are both right on. My recent discover has been the mass airflow sensor. I disconect it no more pop. Doesn't idle but no more stumble. So i'm going to try new maf sensor. Apretiate the suggestions.