RPM Jumping

Merit · Oct 1, 2006

2001 4.7 Durango
Recent work - clean throttle body and TPS, change transfer case fluid

Problem - took a 200 mile trip this weekend. about 50 miles from my destination, I noticed my RPM was jumping from about 2200-2400ish. Cruise was on and speed was set at 74. Coming back today I paid more attention. The jumping didn't start until about 30 minutes into my trip. Then it'd jump every few seconds. The truck didn't accelerate or decelerate - speed stayed the same. After about an hour I filled up. After I did that, it jumped again at about 30 minutes, but it was brief - not nearly as consistent. Then, for a long time it just stopped. As much as I could pay attention, it appeared to only do it every so often. As a test, I took it out of OD - no jumping. At lower speeds it doesn't appear to jump either. Idle is fine as well.

Any thoughts? Could it be the battery going?

Thanks - Mike

Silver Ghost · Oct 1, 2006

Sounds like it still might be your TPS.
You might want to change it out this time rather than clean it up. I went through the same thing - cleaning worked for a while, but finally had to change it.

Joe

iamrazor · Oct 2, 2006

Clean the TB + TPS? What /how did you do this? Is it worth it? What did you use?

Silver Ghost · Oct 2, 2006

iamrazor said:
clean the TB + TPS? What / How did you do this? Is it worth it? What did you use?

I used GumOut Carb Cleaner. Sprayed it itnto the TB while the engine was running - just be sure not to stall it. Also took the TPS off the TB and sprayed the mechanical side down with carb cleaner as well.

Joe

iamrazor · Oct 2, 2006

Results? Is there a thread here documenting the procedure?

IndyDurango · Oct 2, 2006

To clean the TB, get a can of SeaFoam. In park and hot, slowly pour some Seafoam down the TB while the engine is running. It'll bog and want to die, but don't let it. Pour about half of the can down the TB and then let the D run and run at idle. It'll smoke up a storm, while washing and cleaning out the gunk from the TB on down (someone called the fire dept when I did mine due to the amount of smoke.) When the exhaust is back to invisible, you're done.

Make sure you're in a well ventilated area (i.e. not in the garage)

IndyD

iamrazor · Oct 2, 2006

How would I know if they need a cleaning?

Should I pop off the air hat or just shoot it into the instake?

Silver Ghost · Oct 2, 2006

Whatever cleaner you get, SeaFoam or GumOut or?, take the air hat off and run the cleaner straight into the TB. Just follow what Indy says about not letting it die.

Joe

jimbo · Oct 2, 2006

Spraying the TPS mechanical side won't do a thing, you need to replace it. Temporarily, taking it off and tapping it on a hard surface it might help.

FSTDANGO3 · Oct 3, 2006

Just get a new one. Cheap insurance.
Steve
DOC Pres

5wishes · Oct 3, 2006

I've always been scared of the idea of 'pouring' something down the throat of a running motor. Get a small aluminum pan or other container and clean the TB and the IAC sensor by hand. Replacing the TPS should only run about $40. Take some carb cleaner to the TB and to the mechanical side of the IAC (gently.) Use a toothbrush to get down into the tight spaces on the TB. Put it all back together and you should notice a huge difference.

This set of instructions was posted on here about a year or so ago.

Five-o · Oct 3, 2006

I had the TPS problem an few years back and it was replaced under warranty? IT"S BACKKK!

Time for a trip to the auto store when we return from our trip. With 104K I guess I really can't complain.

iamrazor · Oct 3, 2006

Final dumb question:

How do you know it needs to be cleaned? I've noticed the D do some erratic ldling when at a stop light both before and after the battery went dead and needed a jump. I've read here the D's are very finicky about batteries. Truth/rumor?

RobDA · Oct 3, 2006

Truth! Very finicky. You'll see many mentions of the "Dead Battery Club" here? myself included. It'll start fine, but won't hold an idle. If the battery isn't putting out 100%, you'll know it. Happened to me right after I had Shmoop shipped out here in early '03 and, in a moment of stupidity, I replaced it with a cheapo Costco battery (Hey, who needs cold cranking amps here in HI, right?) It lived until about 2 weeks ago and suddenly, my remote start wouldn't work. Hard to start, wouldn't hold idle at first startup. I pop the hood and see the battery's cracked! Oh well? Got smart this time and replaced it with an Optima Red Top. Hooray nice strong starts!

IMHO, the TPS is a cheap enough part that if you think it needs a cleaning, just replace it. Cleanings just seem to put off the inevitable by a month or so.

Merit · Oct 9, 2006

Follow-up

Follow-up for the archives.

Replaced TPS - all is well. No more bouncing RPM.

Five-o · Oct 9, 2006

Mine as well. Took the engine a few minutes to figure out where to settle the RPMs.

RobDA · Oct 10, 2006

Glad to hear it!

Unnamed · Oct 11, 2006

So, by pouring it down the TB, you're actually cleaning the TB?

I just put mine in the fuel tank a few weeks ago. Not that I thought it really needed it, just did it for the helluvit. Anyway, I'm just curious if this would be cleaning anything that say the injected fuel isn't? Granted its much more intense.

Edit: aside from the TB itself of course.

Adde · Oct 23, 2006

Is it kind of self explenatory when you get the TPS or does anyone have instructions on how to replace it? Also, where can I buy it haha.

Was just on a trip of 120miles back and forth. On the way back, the rpm's started jumping.

RPM Jumping

Merit

Silver Ghost

iamrazor

Silver Ghost

iamrazor

IndyDurango

iamrazor

Silver Ghost

jimbo

FSTDANGO3

5wishes

Attachments

Five-o

iamrazor

RobDA

Merit

Five-o

RobDA

Unnamed

Adde

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