On my 90 rs 305tbi...two days ago at idle it just started loading up and missfiring but anything after idle and it's fine.I've replaced the cap,rotor,plugs,timing chain and gears,plugwires and the coolant sensor.I'm not getting a service engine soon light so scanning it wouldnt help me in the least.Any ideas?

 

Ok since i posted this i have narrowed it down to the 2 things that seem to be causing my issues...O2 sensor and air pump,i can unplug the O2 and it runs fine or i can undo 1 of the air pump hoses and it also runs fine.Driving myself insane attempting to figure it out...i had a friend bring his scanner over and let it run for awhile on diagnostic,turns out it says it's constantly running lean but in reality isnt.The old O2 was bad hence is why i changed it but it still says it's running lean and dumping fuel unless i unplug the air pump or O2.I'm truly at a loss on this one.Only thing i can think is maybe the module or distributor itself considering it normally only acts up once it's warm.Any ideas?

 

Look at your temp sensor wiring/connector very carefully, you might have a short. Same with wiring from o2 sensor.

Or???

TA