Loss of power when warm

[Cmoore831]

So I have a 96 explorer xlt 4.0 ohv and can't seem to figure out what is wrong with this truck. You can be driving along for about 20 minutes and when it gets warm it's like the truck doesn't advance in timing; won't go past 20mph uphill. I have replaced fuel pump, fuel filter, fuel injectors, o2 sensors, ecm. And I am at my wit's end for a faulty part. The only thing that I can think of at this point is the camshaft position sensor because when warm the truck acts like it is not advancing in timing.

 

[MrQ]

Is it idling rough when warm? Is it stumbling during acceleration? Are there any CELs?

Have your tried the cleaning the IAC and the MAF? I would also check the throttle position sensor.

It sounds like this is happening when the system is kicking over to an open loop and starts using the sensors for information rather than the profile in the ECM.

 

[974X4BLACKSPORT]

Check and make sure the ECM/PCU (computer) is receiving the proper engine temperature signal from the engine, if not, then the computer will think the engine has just been started cold, all the time, and will have higher idle, and wrong a/f ratio. If you dont have a scanner that reads code AND can show live engine data from the sensors as it is running, then you need to get one, they are not that expensive and is a hell of a lot cheaper than throwing parts at it.

 

[Cmoore831]

Bought a new throttle position sensor cause the old one was toast there are no cels and it does not udle rough when warm only when I hit the accelerator, cleaned the MAF sensor and the iac when I replaced throttle position sensor.

 

[MrQ]

Hmm, the kicker is this only happens when it gets warm... I am thinking clogged cats. Only thing that would possibly not throw a CEL, heats up as the truck warms up, and can cause poor performance like you are having.

 

[koda2000]

Clogged cat, muffler or exhaust maybe? Have you done a compression test? I don't think the cam sensor is your issue. It's purpose is more for fuel injector timing. Also I'd think you'd be getting a CEL if the CPS was bad.

 

[Cmoore831]

Removed the cat cause I thought the same thing and I'm still getting this issue.

 

[Cmoore831]

Haven't done a compression test though I'll run the test when I get home