1999 F150
144K miles
5.8L engine V8 Engine code L
4x4 extended bed.
Please help me if you are experienced enough to tackle this.
My 1999 f150 skips a little at idle. It is worst when on highway and above speeds of 70MPH. It is also very noticeable at stop lights. You will notice it run smoothly for a 40 or so seconds and then a little skip or miss once in a while. This problem has been on since I bought the truck at 100k miles. Since then, I have done the following:
Replaced all spark plugs from bosh to Motorcraft. (at 130K)
Replaced all injectors at once (130K)
Replaced all coil packs at one. (130K)
Replace EGR valve
Replaced fuel filter. (six months ago)
Replaced IAC
I am at my witts end. I took it to my mechanic and after 3 days they could not find anything. They recommended I take it to the dealer. Well I just took it there and the tech claims the following repairs will fix it.
Replace #6 Coil and spark plug
Flush fuel system
Flush coolant system.
Total cost $588 plus tax.
I do not think this is the fix because as you can see from my write up above, I have once replaced plugs coil and injectors all at once and that did not fix it.
However, I am having an independent store do the flush of coolant and fuel system right this moment and when they are done I will change the #6 coil and spark plug myself.
Can someone chime in?
There is no engine code.
144K miles
5.8L engine V8 Engine code L
4x4 extended bed.
Please help me if you are experienced enough to tackle this.
My 1999 f150 skips a little at idle. It is worst when on highway and above speeds of 70MPH. It is also very noticeable at stop lights. You will notice it run smoothly for a 40 or so seconds and then a little skip or miss once in a while. This problem has been on since I bought the truck at 100k miles. Since then, I have done the following:
Replaced all spark plugs from bosh to Motorcraft. (at 130K)
Replaced all injectors at once (130K)
Replaced all coil packs at one. (130K)
Replace EGR valve
Replaced fuel filter. (six months ago)
Replaced IAC
I am at my witts end. I took it to my mechanic and after 3 days they could not find anything. They recommended I take it to the dealer. Well I just took it there and the tech claims the following repairs will fix it.
Replace #6 Coil and spark plug
Flush fuel system
Flush coolant system.
Total cost $588 plus tax.
I do not think this is the fix because as you can see from my write up above, I have once replaced plugs coil and injectors all at once and that did not fix it.
However, I am having an independent store do the flush of coolant and fuel system right this moment and when they are done I will change the #6 coil and spark plug myself.
Can someone chime in?
There is no engine code.
Senior Member
You could still have a bad coil(cop) even though you recently changed them. Not all brands of them work very well. Most people on this site seem to buy them off of Ebay from the companies named Global, or uneek.
My point is that even when I changed them all with cop from global on ebay, it never solved the problem then. I just picked up truck after fuel system flush a couple of minujtes ago. Truck still runs like crap. Will change #6 COP and plug tommorrow.
Senior Member
Is the wiring harness to the cop in good shape. Sometimes rodents and other critters will chew on them. It could be in a place out of your view. Maybe you could use a volt meter to see if the coil is getting power and signal.
Out side of that, swap the coil with another one that is easily assessable to see if the miss moves also.
Out side of that, swap the coil with another one that is easily assessable to see if the miss moves also.
After changing the #6 coil and plug, truck now runs very well now that I have taken the truck on the highway.
The lesson learnt here is to never use the Aftermarket coils again. This is because, the set I bought from Global on ebay must have had a couple of them bad from beginning. I have replaced some over the months but since the #6 never sprung a code, It was never changed. But since I always had the problem even immediately after changing the plugs and coil, I am inclined to believe the #6 coil was bad from inception.
The lesson learnt here is to never use the Aftermarket coils again. This is because, the set I bought from Global on ebay must have had a couple of them bad from beginning. I have replaced some over the months but since the #6 never sprung a code, It was never changed. But since I always had the problem even immediately after changing the plugs and coil, I am inclined to believe the #6 coil was bad from inception.