Help Needed Momentary power loss - What is my Truck telling me?

[Friis]

Over the past 500 miles or so I've had a strange experience with my stock Y2K F-250 4 times. When driving 40-50 mph and letting go of the throttle the "emission system" light comes on and power is gone. The engine is in idle as the truck is decelerating and there is no response whatsoever from the throttle. After about 5 seconds the light disappears and power is back. On two occasions the trans shifted violently from 1st to 2nd and back to 1st and 2nd again and repeated this 4 or 5 times. After that everything was completely normal. On the last two occasions the were no hard shiftings.
After the first time I thought it to be some kind of glitch in the computer system and thought nothing more of it, but now I think my truck is trying to tell me something... Every dipstick checks out fine. No burnt smell or low oil. And the ride is completely normal between theese strange events.

Please help. Thanks.

 

[BIG JOE]

Helloooo Denmark !!!

How old are the Batteries ?

First thing I'd check is the Battery condition. Load test them [INDEPENDENTLY], then clean and inspect the cables and connections, Clamps & Posts.

You would be surprised at what weak batteries or dirty, loose, corroded connections can cause.

A GOOD place to start trouble-shooting.

Joe

 

[Friis]

Hello Sunny California!
Ok, thanks. Ill try that. I don't know how old they are. They were on the truck when I bought it this January. I could check with the previous owner.

 

[stroker21]

My 97 OBS psd was doing the same thing. I replaced the cam sensor and haven't had any problems since.

 

[Friis]

My 97 OBS psd was doing the same thing. I replaced the cam sensor and haven't had any problems since.

Really? How often did it happen to you? And did it get worse or more frequent?

 

[BIG JOE]

Really? How often did it happen to you? And did it get worse or more frequent?

The CPS (Cam Position Sensor) would the next thing to Trouble shoot.

As it begins to fail, it can create the symptoms you desribe. Most CPS's just Quit, after only a few stumbles. It's Not repairable, just replace it.

Another question for the previous owner ?? Has it ever been replaced ?

Even if it has.. new(er) ones have been known to fail. There is a "New & Improved" CPS from FORD. (A Free Recall replacement, including labor... not sure'bout Denmark though)

 

[stroker21]

Really? How often did it happen to you? And did it get worse or more frequent?

It was random. It got to when I was driving down the road it would start cutting out. I would bet it is your CPS. There only like $30 now.

 

[Friis]

OK. Thanks. Now i know where to start. I did a bit of research and found out where the CPS is located (passenger side, front of engine, best reached from underneath of the vehicle) but what does the CPS do? Yes, sensing the position of the camshaft, I get that , but why this influence on the function of the engine?

Also, I tried to check the recalls of all F-250s from 1999 to 2001 on this site: Ford F-250 Recall Reports & Recalls at UsedCarsPlus.com
But it didn't say anything about the CPS. Is there somewhere else I should look?

 

[95_stroker]

what does the CPS do? Yes, sensing the position of the camshaft, I get that , but why this influence on the function of the engine?

The CPS lets the PCM know the position of the cam basically to set the injection timing. If the PCM knows where the cam is, it knows where the pistons are and it lets the IDM fire the injectors. No CPS signal, no fuel is injected.

 

[arrowstrap]

Same O' here... replaced the CAM sensor and not a flux in power since!