I have 1993 S10 Blazer 4.3 tuned port. I have taken it to 2 shops that are fairly knowledgeable. Fuel injector assembly has been checked, sensors checked and replaced to attempt something. It runs smoother after coming up to temperature, but wont pass emission test. The last shop I had several hundred in troubleshooting labor and stopped when he said maybe wiring to ecm, ecm or ecm chip. This was about a year ago and now need to pass emission test. I purchased another ecm and swapped it and it was no better. What do I do change chip?

 

I guess I should mention that I have tuned the engine up. New cap, rotor, wires and plugs with E3.

 

There might be an issue... These trks only like ac delco ignition parts! Anything other and u run into issues.....cap,rotor,plugs & wires... It might be a long shot, however I wouldn't use e3 plugs.........

 

I used premium tune up parts and this problem was an issue before the tune up.