Erratic RPM @ low speed

IVAN355

MEMBER
CHRYSLER LHS

Hello I have a 1996 Chrysler LHS with 180,000 klms, 3.5 engine.
The problem is at low speed coming to a stop the tack will drop to around 500 then surge to 1100-1200 rpm and almost stall.
This all started when the water pump and timing belt was changed. I have changed out the TPS, cam sensor and done a regular tune up with new plugs and wires.
The car has been in the shop and on a scanner with no codes issued. The mechanic did make some adjustments with the scanner and it did run better for a day.
The car runs worse in cold weather. Also when at a stop sometimes the car will idle low at about 600 rpm, but if you put it in neutral then back in drive it will be back to normal at 750.
Can anyone give me a clue on what this problem would be? Any help would be much appreciated.
Thank you in advance Ivan.

4 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Inspect and test the PCV valve and EGR systems and then comeback

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Saturday, March 17th, 2007 AT 3:52 PM

IVAN355

MEMBER
4 POSTS

Hello thanks for the reply.
I have changed the pcv valve, I will run a check on the egr valve.

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Saturday, March 17th, 2007 AT 6:41 PM

IVAN355

MEMBER
4 POSTS

As per your suggestion rasmatas over the weekend changed the PCV and tested the EGR valve. The PCV valve was a couple of months old but changed it anyway and the EGR valve tested good.
Also recharged the battery and found that it was down on liquid, checked the vacuum lines and found them all good.
Took the car for a couple of hundred klm run on Sunday and the problem still persisted. Not at every stop did it surge but at lest 50% of the time.
Would you have another suggestion to try?
Thank you in advance Ivan.

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Monday, March 19th, 2007 AT 4:25 AM

RASMATAZ