[poncho-mike]

My neighbor asked my opinion on his 2006 E-150 Ford van. I drove it and noted the following symptoms.

When starting cold, it runs fine. The torque converter holds on a hill and I didn't have to hold it back with the brakes.

Under acceleration, everything seems to be fine. It goes through all four gears at what seems to be the appropriate shift points, and is fine coming down when stopping at a stop light.

Once it gets warmed up, it begins to act up. It is fine when stopped and under mild to moderate loads or when accelerating. When you let off the gas or are under light load, the tranny seems to want to jump around to lower gears. It seems like it can't make up it's mind what gear it should be in.

The check engine light is off, and has never come on.

I'm thinking it is some type of electronics problem such as a bad sensor. When the engine warms up and begins monitoring the sensors, it starts to act up.

The tranny fluid is clean, and it never exhibited any signs of clutch slippage under load.

Any thoughts?

Mike

[Derding]

Might be a slight vacuum leak around intake manifold. I had a Ford truck that did the exact same thing once warm. Everything was fine until it needed to downshift while coasting. Then it would clunk in and out of different gears. Engine seemed to run fine too. Would have never guessed it was a vacuum leak, but a new set of intake gaskets fixed it. I've also heard a bad throttle position sensor can cause these symptoms.

[GpFreak]

Trannny problems may not trigger a check engine light, sometimes it's a wrench or gear cog lamp. I would still scan it for codes. Could be a temp sensor/harness problem, also depending on mileage a fluid and filter change never hurts and would have to be done to get at the sensor anyway. It helps if you have the ability to monitor the temp sensor with a scanner. It could also be a programming issue, a 15 minute battery disconnect (both cables) and the extended drive/learn scenario my help.

[Alvin]

Originally Posted by GpFreak

Trannny problems may not trigger a check engine light, sometimes it's a wrench or gear cog lamp. I would still scan it for codes. Could be a temp sensor/harness problem, also depending on mileage a fluid and filter change never hurts and would have to be done to get at the sensor anyway. It helps if you have the ability to monitor the temp sensor with a scanner. It could also be a programming issue, a 15 minute battery disconnect (both cables) and the extended drive/learn scenario my help.

IMO - BINGO!