1990 Chrysler New Yorker Engine runs rough when cold.

Tiny
MCISME
  • MEMBER
  • 1990 CHRYSLER NEW YORKER
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 130,000 MILES
Hello. My car starts up fine when its cold but after a few minutes it runs rough. When the car is warm I dont have any problems.

For instance: Ill start the car. Leave and get about 1/4 mile down the road and then the car starts running rough and backfiring. I usually give it the gas and it will stop. It only does this when the car is first started up or when the car is fairly cold still after driving.

I have changed the fuel pump/strainer, Fuel filter and coolant temp sensor. I was told it might be another sensor.

Any help would be appriciated.

Thanks.
Monday, March 23rd, 2009 AT 10:00 AM

7 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Has the check engine light come on?
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Monday, May 11th, 2009 AT 7:21 AM
Tiny
MCISME
  • MEMBER
  • 11 POSTS
No check engine light. I had the fuel pressure checked and it was great. I also changed the tempurature switch but I was told that is just for the guage, which I found to be true that the temp guage runs off the temp switch, not sure if anything else runs off the temp switch though.
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Monday, May 11th, 2009 AT 9:18 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
There is a temp sensor that tells the computer how rich to run the fuel mixture based on temp. Cars with fuel injection don't have a choke like the old ones. If that is ok, I would check for vacuum leaks.
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Monday, May 11th, 2009 AT 12:04 PM
Tiny
MCISME
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Yeah the coolant temp sensor is for the fuel rich/lean, that was replaced. The temp switch is for the guage.

Also I want to point out that sometimes when I first start the car it will run fine for a minute or 2 and then runs rough and you can hear the air intake sucking air loudly. The idle will go up and down also. This has not happened in a while.

I will check for Vacuum leaks and get back to ya. As far as I know there wasnt any but ill double check.

Thanks
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Monday, May 11th, 2009 AT 1:03 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Check the EGR valve too for it sticking. Timing and vacuum leaks are good for causing backfires.

Let me know what you find.

Joe
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Monday, May 11th, 2009 AT 1:32 PM
Tiny
MCISME
  • MEMBER
  • 11 POSTS
I looked for the EGR valve and have great knowledge of cars and engines and couldnt seem to find it. I looked in my Haynes repair manual and where it shows the egr valve for a 3.3L engine there is none. Hynes Manual shows it bolting to the top of the air intake and there is a bolt hole and a electrical hook up, but no valve. I swear I thought I saw it on that car before but I looked as best I could and couldnnt see it.

There is no vacume lines unhooked as if it were to go to the egr valve. I will have a mechanic friend show me where it is ifmy car has one.

The repair manual says some of the problems of a bad egr valve is rough idling and car stalling and stuff, it was making me think it was the egr valve until I couldnt find it.
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Sunday, June 7th, 2009 AT 7:02 AM
Tiny
GALLAWAYCG
  • MEMBER
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These vehicals do not have a egr valve unless its from california
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Monday, June 4th, 2012 AT 10:57 PM

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