meb

About a year ago, my 2000 F150 175,000 well maintained 5.4 mobile 1 was moved to a light duty status. Truck ran perfect. So it would see duty once or twice a week to pick up some hay or maybe tow my boat.

It picked up a shudder; kind of like you are driving over 2 X 4(s). I've seen and read many posts on this subject. It went to the Ford dealership 3 times with them having me throw money at it without ever fixing the issue. And its throwing no codes.

The shudder is associated with the pre-ignition sound. It mainly happens after the vehicle is warmed up and it doesn't happen all the time. Sometimes once a month. Sometimes every day. When it does occur, I have tried taking it out of overdrive but this does not change the behavior. And most of the time it seems to all occur at a steady cursing speed (lets say around 50). This has been going on for over a year now.

Here is a list of whats been done to it; by me or the dealer


Vehicle speed sensor
throttle position sensor
new plugs / boots
couple coils replaced (by dealer with no code thrown)
crank position sensor (the one NOT behind the compressor)
All oxygen sensors
MAF is clean
Air filter clean
injectors serviced
gas filter new
Anti-studder added to trans
Trans fluid replaced

I'm fairly technical but I'm at a bit of a loss what to do.

meb

Well interesting response to my own post. Turns out I had the fix but I made a mistake. The is a little rant to buy OEM parts. I bought an aftermarket MAF and the dealer said the thing was all over the map and didn't conform to spec. One problem down. The other problem (and mentioned on another post here) was the little air pump near the throttle body. That and the hose, which was leaking, along with the MAF turned out to be the issue. The air intake pump was noisy and I figured that needed to be replaced but let the dealer do it at that point due to reliance on the truck (I own a small farm).

*WOW* - 1.5 years later and 5 trips to the dealer and its fixed.

papa tiger

It's exciting what sitting around does to your vehicle, probably like just sitting around oneself. Ol parts fall apart and new aftermarket blo-some wind. Get UR self a present a OBD II reader that graphs in real time. It will give U a lot of happiness. Then run all the pids while driving with warmed up truck and note them for future reference. Best present U can get UR selv other than a new F150 LOL

meb

Tiger, yes, totally agree what happens when your truck sits around. I have some old Chevelles that I start once a week during the Winter. There are lots of posts on that topic in the Chevelle forums (www.chevelles.com). Start versus letting it sit. I would have sold my truck to my GrandMother before I took it off the road. And then the trouble started.

I do have a real time ODB II data accumulator. The problem was that the lean condition and the bucking happened rare enough that I couldn't "catch" it. As it really turns out, that air hose, IMO, was the problem. Basically you have an unwanted air source entering the engine but nothing metering it so it doesn't become part of the "timing equation." Some other huge problem, but similar, is when the air intake leaks. Not so prominent on the 5.4 as the 4.6's.

Take care. Heading out later for Christmas day. Merry Christmas everyone!

papa tiger

Good Motoring !