i have a number 2 cylinder misfire, the check engine light flashes constantly. The truck doesnt seem to be running any rougher, but when i take out the number 2 plug it looks brand new and has a decent amount of gas on it. ive tried swapping the coils, checked for spark, changed the fuel injector, spark plugs, and wires. the plugs are all motorcraft. Also the cats are hallowed out.

Truck is a 1997 F150 4.6L 189k miles

thanks in advance for your help,
Billy

 

How are you running with the cats hollowed out? Must run like crap. You need at-least ONE cat per side with the stock tune or she ain't gonna run right.

Check compression, see where your at there.

You should have a solid light (CEL) . Blinking means Misfire yes, but constantly, non-stop ? That's unusual.

 

actually it ran pretty much the same before and after the cats were hallowed out, but that may be because the exhaust manifold was cracked at that time. It has always had the check engine light on solid, until it decided to flash all the time recently.

I forgot to mention when i unplug the injector it sounds like it backfires into the intake. only on the number 2 cylinder though.

Ill see if i can get the guy i work with to bring over his compression tester.

thanks,
billy

 

Well , the engines not running right to begin with. If you gutted all four cats, -that will inturn damage the motor long term. Your simply not tuned to run that way. The CEL must be on all the time.

Other than that, you can go thru the fuel system, - install a new filter then check pressure.

Compresion after. You'll most likley find the problem since the other things tried didn't reveal anything.

 

do i really need all four cats or just the first two? Because if i fix this problem i might go ahead and put some cats on it. i already replaced so much on this truck it would be a waste to just blow it up. lol

 

dump the 4 and go to a single on each bank... some decent name brand cats too, dont cheap out....

 

too long w/o backpressure and your valves tend to bend......

 

which cats do you recommend?

 

hi-flo magnaflo's and a decent muffler also

 

Right, Magnaflows -




But those usually work best right behind Long tube headers. -



____________________

Or you can run just stock forward Cats and still be within parameters -

 

I finally checked the compression on the No. 2 cylinder and it was 110, does that seem low enough for it to miss?

 

Check the other cylinders - you are looking for a variation.

 

No, it should fire with that compression.