THe motor is in my 88 s10 blazer (95 LT1 out of a camaro). I have the egr programed out. New wires and ac delco spark plugs. Stock exhaust. The O2 are a year os so old but are not ac delco. I wiped them off when I exhaust reran yesterday. The IAC is also a year old and new opti is less then a year. Four new injectors on one side because 2 didn;t seem to function and tested out poor. I have swapped the other 2 good ones in every positioon with the remaining old 4 to no success. Still a bad hestiation or stumble and intermediate idle. It bounces between 800-1000 on idle and has a hestiation at take off. Any suggestions to give me a direction to start checking?

Thanks,
Howard

 

O2 sensors that aren't original can cause a whole lot of problems like running rich (black smoke) to the stumbling you had. Engine electronics (opti, o2 sensors) should only use AC Delco.

 

clean the iac and maf.