TPS? CPS? Fuel Pump? Help!

[najnad]

Ok, this new problem cropped up during a long drive (6+) hrs two weeks ago and just happened again during a 2 hr drive. It doesnt seem to pop up in short trips around town.

the problem:

- Engine loses power suddenly, as if I lifted off the gas pedal. Engine continues to run and will regain power if I push the gas pedal in more. No real consistency as to when it happens...no specific speed or rpm when it happens more or less. Do occasionally get CEL and P0121 when this occurs, but not all the time and does clear. Had a recent smoke test, no vacuum leaks.

My initial thought is the TPS is going bad, but would like to hear if others have had this same issue and replacing the TPS is the solution or not. The TPS is almost $100, would hate to replace it and then still have the problem.

thanks!

[ThreeD]

There's a way to test it that's outlined in the bentley manual. Any CEL?

-a fellow Ellicott City resident

[najnad]

Yes, CEL and P0121, but does not always pop up every time the loss of power happens.

[gemolken]

Do you have an AFR gauge installed? what changes happen on the gauge when this stumbling occurs?

I'm gonna guess the MAF sensor.

[najnad]

no AFR gauge. I will try cleaning the MAF first...see if that clears it up.

Keep the ideas coming...thanks!

[najnad]

UPDATE: I cleaned the MAF sensor with the CRC MAF cleaner...the problem has (mostly) gone away. During 2 two hour runs, I only had the stumbling occur for a few minutes in each run. So I might clean the MAF sensor again, but it seems to have mostly solved the problem. Maybe my TPS is going bad and has a dead spot, but with the MAF cleaned it changed the throttle position I use for the same speed?

At any rate, the MAF sensor cleaning did make an improvement on on overall running/acceleration of my car...so that is a win even if I do end up having to replace the TPS anyway.

[najnad]

Update: Still had the hesitation, so I replaced the TPS and it is gone now.