all of a sudden it runs like crap

[MNSubbie]

I have a 98 F150 with 229K on it, and the old 5.4 has been running absolutely perfect with no signs of trouble----until tonight.

It starts right up but quickly falters and dies. If you keep your foot on the gas you can keep it running and even drive it, but it chugs and has low power, and will not stay running if you take your foot off the gas pedal. Seems like it only running on a couple cylinders. No check engine light.

Does it sound like ignition or fuel? What does the cam sensor do? Any clues or advice would be appreciated before I dig in and try to fix the wrong thing.

[Davescort97]

Pull the plugs and read them. They will tell you if the cylinder has been getting fuel, but not firing (wet plugs) which would indicate ignition problems or if they are dry would indicate not getting any fuel. Check for fuel pressure at the rail. Check your ignition wires. Check the PCV valve and hoses and check the hoses on the intake for a vacuum leak.

[bf5113]

I know this is a stretch but I had a similar problem a while back and I finally figured out that the cooling lines from the transmission to the radiator were leaking and squirting trans fluid on the serpentine belt causing it to slip and the truck to falter after starting up. Good Luck!

[MNSubbie]

Almost embarrassed to admit what the problem was-------but maybe this will help someone else........
Turns out the elbow that connects the PCV hose the the rear of the intake manifold had popped off (last person to work on it did not use a clamp). I got a new elbow at O'Reilly and clamped it on----runs like a champ again. Thanks to those to replied and offered assistance

[Franco2112]

MNSubbie,
You are commended for letting us know what you found. It will help someone later.
Again, thanks!