84 3.2 missing?
 

Hi all. I'm having a problem with my engine that has just started happening. The idle is fine around 8200. Its running like an old Chevy with a lumpy cam. car is shaking a bit. I was thinking it was a plugged injector so going by the Bentley I disconnected each injector one by one to see if there was a change is rpm. When I pulled #3 there was no change like the other 5 cylinders. So I figured it must be bad so to check it I swapped it with #1. Same symptoms. tried switching the spark plug with #1 same thing. Switched spark plug wire with #2,same thing. I also switched the injector wire from 2 to 3 still no fire. Spark is good. Next is a compression test tomorrow after work. Am I going in the right direction? could it be a bad valve? I checked the valve clearance it was a bit tight, but not enough to have the valve hanging open. Engine has 140K on it.

Mine does a similar thing but clears itself after the engine warms up. Believe my valve guides r showing some wear Is yours missing all the time? You might try some BK 44 and see if you can clean out the injector and be sure u r using the right gas like chevron that includes additives.

Bob

Always use premium. It just seems to be at idle. I know its not a plugged injector, I switched #1&3 around. #1 is fine after. Exhaust is very rich.

Move the injector harness from 2 to 3 and 3 to 2, I think they should reach. You want to be sure it's not a wire harness issue on inj #3. The injectors in the 3.2L are batch fired, meaning they all fire at exactly the same time, all 6 are wired in parallel. No harm done if you swap harness wires around. Could be that inj harness #3 has a bad pin or wire, so moving it to cyl 2 will help identify and verify that the cyl #3 injector harness is good.

Also, if you have infrared temp gauge take a temp reading at cyl #3 exhaust port and compare to other cylinders at idle. If #3 is cold you know it's dead.

EDIT: I missed it, you already swapped the wires. In this case I'd still take a temp reading on Cyl #3 exhaust port. Also disconnect the IdleControlValve when doing the injector tests. Sometimes the ICV will compensate the idle very quickly and you won't notice the idle drop.

The O2 sensor is on Drivers side bank so if Cyl #3 is dead then it's pumping air into the LHS heat exchanger and this extra air has tons of O2. This extra O2 is seen by the O2 sensor as a false lean condition because the O2 sensor simply looks for O2 content. Then the DME sees this as a lean condition and fixes it by enriching the the mixture and now you have the other 5 cylinders suddenly going rich. Bottom line is a dead cylinder in any O2 closed loop system causes over rich conditions in the remaining cylinders.