Hey guys. I have a 97 F150 4.6, 73000 miles on it. Bought on a real good deal, although it sat for at least a year and 1/2 without being started or moved. I changed everything, plugs, wires, all the filters...I still have a miss, but only when I stop at a light and its for a couple of seconds then it will stop, and back again a couple seconds later. It also seems sluggish on takeoff. I had a missfire on the #7 cylinder, but after I changed plugs and wires the light went off. Could it be my coil pack? Any help would be great, thank you in advance.

 

You possibly have a injector problem. Check your spark plugs for one that looks different from the others; wet, white, not like the others, ect. Also look at the EGR. Clean the carbon out inside.

 

Do you think it would be a good idea just to go ahead and buy the complete set and replace them all?

 

I have massive misfiring problems right now.... They've been coming and going since I hit the 95K mark or so, 97 F150 with the 4.6W. Anyways, the state yours is in now is the BEST I can get mine to, with new plugs, wires, and coilpacks.

 

Mine is about to drive me nuts, it'll almost quit at the stop light the idle gets so low, then it'll line back out and run smooth...back and forth back and forth. I'm going to clean out my EGR valve and my intake tonight and see what that does for it. If that doesn't work I might throw it in the river....LOL

 

OK boys I fixed it. I took off my air intake tube and sprayed some carb cleaner on the flapper, it had quite a bit of carbon build up. I also took off my EGR valve and inspected it, it was bad dirty, I took some mass air flow cleaner and cleaned it out real good and while I was at it I cleaned up my mass air flow sensor. I think the real culprit was my EGR valve though, it was either letting to much air through or not enough at idle, causing the miss. Thanks for the help.

 

Got my miss cured( I hope) Was getting the code P0303 but the miss was sometimes gone.Dropped the truck off at one mechanic and he told me my head gasket was shot( Was never low on coolant,Didn't overheat or blow white smoke) and he said it would cost between 1400 and 2000 bucks.Said "NO",After re-replacing all the plugs and wires I still had the miss. Replaced the fuel filter then both coils still had a miss so I started pulling one injector plug at a time while the truck was running and found that ther was no change when I pulled # 2. Put a new injector in and she runs nice and smooth with no miss,So I guess I had 2 separate problems, A bad plug,wire,or coil and a bad injector.

 

Thanks for letting us know what the fix was. Cyber mechanics is tough!

 

how much was your replacement injector and is it an easy do it yourself or did you have someone else do it?i'm having a bucking miss at highway speeds and sometimes city speeds shifting up and down with light load.

 

My 97 F150 4.6L W is doing the SAME THING TO A TEE,This is after changing all the spark plugs and putting in Motorcraft plugs,new wires,new TPS,fuel filter,and cleaned out the throttle body! It ran better on the old plugs with NONE of the other done, I thought I was doing it a favor.Now I've just about had it,30 day tags still on it and I'm about ready to sell! let us know if yours still does it after the EGR cleaning,or sombody shed some more light...

 

Cleaning the EGR valve worked great...at least it did for tonight. I drove it about 50 miles and still no miss. I also cleaned down in the port holes on the intake where the EGR mounts. hope it works for you

 

Well that will be the first thing I do in the morning and clean the IAC while I'm at it. Hopefully it solved the problem for you!

 

Got it from AutoZone, $70 and change. It was pretty easy to replace.
1)Disconnect positive battery cable first !!!!!!
2)Remove 2 bolts that hold fuel rail on
3)Lift fuel rail up.(Had to pull very hard actually)The injectors or held in by o-rings in the block and fuel rail.
4)Removed bad injector
5)Used a small amount of multi-purpose grease to lube o-ring
Reverse order to install. Took all of 15 minutes but it was on the passenger side, Drivers side has alot more obstructions.

 

how can i test the injectors to check which one might possibly be bad? i might just dump so injector cleaner in there first so if that helps?

 

It's easy on the passenger side, Much more difficult on the drivers side(more stuff in the way). With the engine running unplug 1 injector at a time and see if the engine runs rougher. If it does re-connect and move to the next one, If it doesn't that injector is bad or stuck closed.