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tbone1871
11-19-2013, 11:15 PM
I have a 1998 f150 with a 4.6L it has been misfiring for a couple of weeks and been sucking down gas like nothing. I replaced the plugs wires coil packs and fuel filter and still misfiring. Any help would be appreciated.
lee reece
11-19-2013, 11:41 PM
Change your plugs?

2007 F150 XLT FX2 SPORT - 5.4l 3V 3.73 LIMITED SLIP EDGE/EVOLUTION PROGRAMMER
tbone1871
11-20-2013, 12:02 AM
Yes I did
RhinoZ24
11-20-2013, 02:11 AM
Air filter? Throttle body? Fuel injectors? All could be dirty. Run some fuel system cleaner through it. And are the spark plugs tightened down all the way?
Jersey_Joe
11-20-2013, 04:50 AM
Coils?
tbone1871
11-20-2013, 05:18 AM
Yes they are tight and I replaced the coils. When I put a timing light on a plug you can see the light is steady one min and braking up the next. The cylinder misfiring keeps jumping around but one seems to be constintly missing.

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And the truck shakes like hell when you are at idle and holding constint rpms
Jersey_Joe
11-20-2013, 05:36 AM
Could b an injector. Could b a bad plug. And can still b a coil pack
tbone1871
11-22-2013, 05:05 AM
How do I test the coil packs
lee reece
11-22-2013, 12:54 PM
Joe is the expert on these models!

2007 F150 XLT FX2 SPORT - 5.4l 3V 3.73 LIMITED SLIP EDGE/EVOLUTION PROGRAMMER
Jersey_Joe
11-24-2013, 06:36 AM
How do I test the coil packs
Hey man. Sorry I took so long to get back. Workin my tail off. Well. Start your truck. Reach back and unplug one of your coil packs. If your engine starts running real bad (don't worry it won't hurt it). Then plug it back in. Ur coil pack is good.
Now if u unplug it and there is no change? Then it's safe to say that the pack u just unplugged is bad. Any car store should carry them. Cheapest I've seen em is 25$ if u have any probes when u test pm me and we will go from there
tbone1871
12-28-2013, 04:30 PM
I figured out the misfire it was coolant getting on one plug and head gaskets for the other. Now I have the truck back together and it is make ins a knocking noise we thought it was n oil getting to lifters so we took the valve covers off and they have oil when I put it back together the second time it still did it any thoughts would be appreciated.
Jersey_Joe
12-28-2013, 04:34 PM
I figured out the misfire it was coolant getting on one plug and head gaskets for the other. Now I have the truck back together and it is make ins a knocking noise we thought it was n oil getting to lifters so we took the valve covers off and they have oil when I put it back together the second time it still did it any thoughts would be appreciated.
Well coolant on your plugs is a sign of a bad head gasket. And as for the tick. Not to sure. I'd have to hear it to give u an honest answer