What the hell is going on?? BackFires

[chaka]

What the hell is going on?? MisFires

This is not mustang specific. Having some problems with my F-150 that are driving me batty.

Last week the truck would die and restart when it cooled off. Figured it was the TFI and I would change it this past weekend. Then it started acting real funky Friday. Major loss of power and then it would run normal. Did this cycle for a bit. Then just ended up with a horrible idle. Definitly a misfire, would backfire every so often.

SO far I have changed the TFI, Coil, Wires, Plugs, rotor, and cap and rewired a relay that had a corroded terminal. Started it up and it still has this misfire. Adjusted timing. Still no good.

Did a Compression check 150-145 across the board except #1 which was 135. But I was using a pushin tester though and could not get a good seal. Will check it again with a screw in.

I noticed one of the Cats glowing. Figured maybe it was backing up So I removed it and now the backfires are really bad.

Checked the voltage to the coil and it is 13.4V.

Sorry for the length But What the hell is up?

 

[DropTopR]

Did you check for any vaccum leaks? Or even maybe the distrubtor is going out.

 

[chaka]

Checked for vacuum leaks I couldn't find any. I know if I remove a plug on the vacuum tree the idle rises.

By dist. going out you mean the pick-up? How do I change that?

Thanks,
Dante

 

[DropTopR]

no, i meant the whole thing. I had a friends car actually wear out the insides of it, and the shaft flopped around. THe car ran like pooey after it did that.

 

[chaka]

I yanked the dist. already and everything was tight. No excessive play.

 

[jrichker]

Backfires through the intake are usually a sign of excessively lean fuel mixture. Check the fuel pump pressure, and if it is low, change the filter. If it is still low, then you have fuel pressure regulator, pump or electrical wiring problems in the pump power circuit. Trucks may have a different fuel pump/fuel filter configuration from passenger cars.