I have a 96 t10 4x4 blazer. The car starts fine and runs good in the morning. As soon as the engine temp starts to rise it starts missing, chugging and back fireing.

I get code 339 crankshaft "misfire" and 341 camshaft "misfire". when I check the timing at idel it's -11. when I move the distributor 1 tooth forward or back the car will not start. When I pull a plug it looks like it is running lean. It always starts and idles fine at any temp.

I can not adjust the timing. I have replaced the plugs, wires, cap, mass flow air, crank sensor, had injecters cleaned and replaced the coil, replaced almost all vaccum lines, fuel pressor seems to be fine.

this all started after I installed a rebuilt long block.

I have taken to two different shop and they can not figure it out....

anyone got any ideas ??????

 

I have the same problem. Did an engine swap on a 97 4.3. Truck starts fine, but as soon as it reaches 2K RPM's it "misses" and tach jumps. I've replaced the CKP, no help. Is there a quick test to perform on the camshaft sensor? Distributor gears looked fine when I initially installed engine. The problem seems to get better and nearly goes away after it warms up....sometimes. Can the reluctor ring slip in these engines? I've also replaced the computer....same issues. Help is much appreciated.

Thanks.