My 89 hatch 1.5L has a misfire problem. The problem only happens when it is below about 3000 RPM under load. If I try to go up a hill in 4th gear below 3000 RPM it will misfire/hesitate, same goes for leaving stop signs, etc.

The problem is worse when the car is warm, so I thought EACV. I unplugged it and it still misfires. Then I thought injector. I replaced the green one, which I think is primary, but that didn't work. I thougth ignition control module in the distributor, but that wasn't it.

Any suggestions? I searched and a lot of people have this problem but hardly anyone seems to know what it is.

 

I had the same problem, so I swapped my entire throttle body and stupid little sensor to the right of the throttle body on my DPFI from my parts car. The problem went away, but I am still having CEL problems, so I am almost 100% certain it is my O2 sensor

 

I saw a guys car which did the same thing, took the distributor off, the screws that hold the icm down were loose, well one was gone and missing the other. installed a new screw, tightened the other down, good to go
worth a try

 

well, i put in the brown injector. then i checked the plugs, they looked worn to **** so i replaced them. then i moved to the valve clearance because i had to take the valve cover off anyway to replace a leaking valve cover gasket. On the test drive, no misfires we'll see how it goes. Not sure if it was the plugs, injectors, or valves (probably not valve clearance, but it was good to check that) because I did all that and then went on a test drive, but the problem appears to be gone. keep fingers X-d. Oh yeah checked compression too, 135-185 with 145,000 miles, not bad!

Edit: ignition module = icm so i checked those screws when i put in the new one (blue locktite on them)