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RPM jumping up in down

M

mteschGTP

New member
Hey guys, I have encountered a small annoyance/problem with my new 2003 GTP 108k miles... I noticed that the idle isn't perfect, it moves about 100 or so RPM consistantly and then while driving in 3rd and 4th/overdrive I get shuddering. The car seems to lurch then fall off then lurch. Now this isn't dramatic, just minor, but the rpm can jump 200-300 RPM quick while accelerating lightly. WOT is no prob, nor is accelerating in lower gears. Could this be the MAF sensor? My MPG's are still good. I took out the MAF and sprayed it with MAF cleaner, but still does the same thing. I tried to test ohms, but my voltmeter isnt high enough grade to tell if the voltmeter is lagging or the signal is actually jumping. Just want to get your opinions before buying a $100 part. Wish I had a known good one I could throw in as a test. Also need to pray it's not the LIM acting up, but could it be?
Thanks in advance
 


What you are describing is typically tune up related. Plugs, wires, cleaning maf and cleaning TB are the usual fixes. Especially if you don't know when this was last done.
 
Yah I thought so too. However there are reciepts for a nice set of pulstar plugs only a few thousand miles ago and i believe he said he did wires at the same time. I cleaned the TB and the MAF already with hefty doses of MAF cleaner.
 
Alright thanks guys, I'll check to see exactly what the plugs were that went in. Seems odd though that this hesitation and rpm jumping only comes in under a load while in later gears though.

Edit: Forgot to mention, there are no CEL's whatsoever. May be comletely unrelated, but my TCS also doesn't seem to be functioning. Light isn't on for trac off, and the button doesn't do anything. was able to continuously spin tires after start up (warm of course ;p) and then pushed the button and still non-stop tire spin. If this is unrelated I'll make a new thread for that issue.
 


Actually ...it's not odd at all.

Lower rpms, more load, more work on ignition system. It's common in our platform. Trust me.. one night WOTGTP thought he had a trans issue..we fixed it with a set of plugs.

Of course..weeks later..he did have a real trans issue.
 
lol i though i had a trans issue had just put new plugs in it already had newer wires turned out to be a bad wire right at the plug burnt threw... i had LTW wires so i got a new set and bam all better
 
For those who contributed in the past... just an update:

Plugs changed: No difference
Wires Checked
Engine scanned

Everything was fine.

So I changed the trans fluid and filter along with adding a bottle of lucas.
This is what my fluid came out looking like! Dont worry I think most of the black specs were in the container before the fluid got there.

IMG_1123_zps77a11388.jpg

Result: A whole new car. Smooth shifting and none of the RPM changes I was seeing before. It's been about a week now since I did it... Maybe 100 miles mixed driving.

May just be a bandaid, or maybe I'll get some good life out of what's left in the transmission. Guess it depends whether it's the clutches or something in the valve body.

So thanks for all the input. Clearly it's going to be a trans rebuild in my hopefully not to near future.
 
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