I have a 2000 F250, SuperCab, 5.4 triton, 100,000 miles. It's been a great truck - got it at 63,000 miles. Once engine warms up, it has rough idle, and shift rough. I can give it gas to RPMs up and it smooths out some but is low on power. If this was my 76 F150, I would guess the vacuum hose off the intake manifold to the transmission came loose. Any ideas?

 

Ever change the plugs? or boots How about Cop's (coil on plug)
Clean the IAC
Clean the maf
Change the fuel filter
Chk the fuel pressure at Idle and part throttle
Just few things to keep you busy
Ever have any chk engine lights?


Rich

 

Had the plugs changed out 3 months ago.
No check engine lights at all.
Thanks for the tips. Will check tonight.

 

Iac and maf would be first then.
Just got your msg
There is a picture in this forum.
Go to the top of the forum ,you will see a Sticky about FAQ's for superduty's
click on the Truck to get in, then engine+transmission in there you will find a picture.

Rich

 

have 5.4 with same problem...... had problem...... vacume hose on back of intake manifold gets heated up against firewall and gets hole in it check this first may save you alot of looking.

 

I found the problem!! Took it to AutoZone from suggestions in the forum from other users that have had engine issues. Even though the check engine light was not on, I had the young man at AutoZone hook up his code scanner. It immediately showed misfire on Cylinder 1 & 2. Went home and took the coil pack and boots off...significant moisture came out of the boot. I cleaned the spring connector with electric contact cleaner, sanded the contact ends, and added a dab of di-electric grease. Runs like a top!

We had a significant temperature inversion from cold to very warm and humid with hard driving rains. My guess is that the Cylinder 1 & 2 suffered a little sweating during the process, thus the moisture being trapped.

 

Have an 08 with the same symptoms. I hope thats my prob too. Much appreciated with the info.