'88 4.1 MPFI XF Fairmont Misfire - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

yeah right · 05-16-2003, 20:44

There's an allen head screw recessed down a deep hole on the air flow meter near the duct that goes to the throttle body - anyone know if it's to calibrate the flow meter or what? Could it be for calibrating the air temperature sensor. The Gregorys manual doesn't even mention it.

The car's been suffering a misfire - mainly on acceleration. It felt like it had a vacuum leak too but I think that my suspicions as to a leaking manifold gasket may have been correct cos I just fitted new ones between the head and injector body and between the injector body and manifold risers & the rough idle has all but disappeared. But the misfire is still there - although reduced somewhat probably due to the leak-free manifold.

I understand that a lot of Fords to 89 have dodgy distributor modules - from the design limitations of the era. Do these symtoms sound like that sort of thing?

Any help is greatly appreciated - it's one of those niggly little things that really gets on my nerves!!!

mongrelEB · 05-17-2003, 04:57

It looks as if you've replaced your leads recently - done the coil lead also?

Other than that, you could try resetting the spark timing.

yeah right · 05-17-2003, 05:17

I don't actually know how old the leads are - the previous owner did them - but they test ok if you stick to the 16k/m rule - should probably replace them as a precaution I guess - and the cap & rotor - so I'll do them tomorrow. The coil looks old too - it's probably due for another one but I'll wait to see the result of the leads & cap I guess. Timings right - 10 deg BTDC with green distributor module disconnected - but it feels flat so I might fiddle with that a bit too.

FordTech65 · 05-17-2003, 16:12

The allen key grub screw you refer to is the idle mixture screw.If your vehicle is unleaded they are factory set and shouldnt be adjusted.Most unleaded one's had a cap on them to prevent tinkering.

yeah right · 05-22-2003, 04:32

Ok - all new cap, rotor, coil (bosch) leads (top gun). Still got that misfire. Also a new gasket between plenum/tubes. Anyone know anything wise about the TFI's? Also - saw some engine oil in the intake tubes -maybe a faulty PCV causing the crap idle?