Jeep Garage  - Jeep Forum banner

Power surge at off idle

1K views 4 replies 3 participants last post by  Cascade159 
#1 ·
I am experiencing an interesting problem on a 2005 WK 5.7. After the vehicle is warm (driving 20 minutes at freeway speeds), then coming to a stop such as a stop light, when touching the throttle, the lurches forward with a less than 1 second significant power on (like stabbing the throttle very quickly). Over the last few months, it has been getting more frequent and more violent (not really the right word). It seems to mellow out with 92 octane.

Then today, I get a P0520 code. Now I am wondering if this is causing the issue since bad oil pressure readings can mess with the MDS. Though, I am not sure why this would be the case coming off idle.

Is it possible that there is a issue with the TPS?

This is very unnerving when the jeep wants to lunge.

Can you imagine what the sheriff deputy next to you at the light must think with the light changes and the vehicle stabs the throttle on its own?:eek:
 
#2 ·
What kind/weight oil are you using and is the level full? Do you have a way to check the oil pressure? That's the first thing I'd check AFTER I cleared the code to see if it comes back within a day or two. If it does, I'd change the oil pressure sensor. I am not so sure that this problem is related to your surging though. I once got this code, cleared it, and it never came back. I still have a new sensor sitting on the shelf just in case though.

It could be a TPS problem, but I think I'd check the transmission fluid level and condition first. When is the last time it was serviced? Does it up/down shift properly? Any hesitation when going into gear, especially the first time after its sat for a while? Does it slam or "ooze" into gear when shifting from reverse to drive or drive to reverse?

Bottom line, eliminate the easy, inexpensive stuff first, and then go from there.
 
#3 ·
Oil: 5-20wt Mobil 1. Oil level well within the safe zone. About 1,000 to 1,500 mile on the current change.

The only issue with the transmission is it will bleed down after sitting a while and not very often. Had it in under warranty and dealer replaced check valve. Transmission is solid shifting. I have about 84k on the vehicle.

When I checked the DTC, it showed the P0520 code as frozen and pending.

I have an oil pressure sensor being delivered. Will probably change it out next weekend.

I am assuming the WK is throttle by wire. As I said before, the car is acting like I am stabbing (stomping on) the throttle. Kind of like the PCM commanding fuel into the intake with the MDS active. When the MDS is deactivated, there is extra fuel and I get the power surge. Or, the TPS could be sending the wrong voltage to the PCM suggesting I have stabbed the throttle.

I am going to start with the OPS and see what that does for the power surge. Its been my experience that getting a code will only require attention later. Since the factory manual states the MDS could be affected by false readings from the OPS, might as well remove that possibility.

Anyone have experience with the Standard Products oil pressure sensor. They generally make good quality replacement parts. It's on Amazon for $26.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top