I have an 01 F150 with the 4.6L,the problem i have is when i start the truck,it idles good,untill i put it in gear,then it kinda surges while stopped,when i accelerate,it shakes and shudders real bad,untill i get to cruising speed,it still does it then,but not as bad,i can turn off the overdrive to keep rmp's up during cruising speeds,and it allmost goes away.The CEL is not on.But it runs bad,to the point I am embarresed to drive it.

 

Have the spark plugs been changed? Fuel filter? Air filter? Do a tune up on it and see where that leaves you.

 

ok,ill try that,do you know where the fuel filter is on this truck?

 

It is inside the frame rail right about where the D. side door is.

I have roughly the same problem and have replaced the IAC, cleaned the MAF, had a motorvac and still the engine stumbles at idle in drive. Today it actually quit on me. I am wondering if a bad COP could cause this. The first time I had one go bad it stumbled under a slight load and at times idled bad. Mine runs fine as long as it is not stopped in Drive, even turning on the AC will help on mine, must bump the idle up just enough. I also have no CEL and no codes.

 

Thanks for the info on the fuel filter.I am beginning to wonder if the rain has something to do with it running bad,I dont use the truck at all during the week because I have a co. truck,so her is the story.We have not had much rain here,then last week we finally got some,before the rain it ran good,the problem started last Sat while it was raining,I did not drive the truck again till yesterday,Sat,when I started it,it ran great,it has not rained since last Sat,so I wonder if the rain may be causing a problem someway,either way,i am changing the plugs,all COP's,fuel filter and air filter,,but my question now is,do you think the rain may have a part in this?

 

Sounds like there is either water getting past the hood seal in the rear allowing water to get into the plug pockets or the humidity is causing a misfire. I would remove the coils and install dielectric grease on the boots.

 

If the cops are bad (no pun intended), the humidity coould have seeped in and corroded the insides. Water and the cops don't mix well.

Its just like an old dizzy and worn out plugs. run good at speed, terrible at idle and under low speed load.

 

Well,i think what i will do to be on the safe side,is to replace the plugs,air filter,fuel filter and the COP's.But now,I have a question about quality of the COP's.Are the ones on e-bay that Global-Automotive sells,are they any good,I am buying Motorcraft plugs,but was wondering about the quility of these COP's.

 

I assume you are talking about the 8 for around $110, as in expensive as they are compared to around $60-$80 for 1 from the dealer I don't think you can go wrong with them. There are even name brand COP's now being sold for around $25ea. out of summit.

 

I finally got around to putting all plugs,COP's,air filter and fuel filter>what a differance it made.I just want to thank all of you for your help.I never realized how much power I have lost over time,it has alot better throttle response now,and the miss is gone,again,thank you for your help