2003 Dodge Intrepid reduced mpg and engine light

Tiny
BSWINEY
  • MEMBER
  • 2003 DODGE INTREPID
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 82,000 MILES
My intrepid mpg went down from 29 mpg to 24 mpg. The engine light came and the shop told me the code said that cylinder no. 1 was misfiring. They said I needed new plugs and wires and my injectors cleaned. I had all this done and it did not stop the problem. They switched fuel injectors and coils from other cylinders and the engine light still came on with the same code and the mpg is still 24. The engine idles rough and when I have the cruise set it will surge maybe 25 to 30 rpm. Enough you can feel it. Also, after you drive it 50 miles or so and the engine is warmed up, if you stop at a light and idle the engine oil light will flash as the engine idles rough. If you speed up the motor just slightly this stops. The engine light came back on and I had it reset. I have driven it about 200 miles and it hasn't come back on but the other problems are still there.
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Monday, March 10th, 2008 AT 6:47 PM

6 Replies

Tiny
MASTERTECHTIM
  • MEMBER
Unfortunately next step is to perform a compression test on the cylinder, it sounds like its weak, possibly from a worn valve, camshaft or valve spring. Its pretty simple to do compression check, have that done and get back to us.
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Monday, March 10th, 2008 AT 7:23 PM
Tiny
BSWINEY
  • MEMBER
They also did that and said the compression was good.
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Monday, March 10th, 2008 AT 8:20 PM
Tiny
MASTERTECHTIM
  • MEMBER
If you have a broken valve spring it will still give you compression. Ok lets not overlook the obvious, have they checked it for a intake internal vacuum leak. I would think so but maybe they are not familiar with it. When at idle and engine is running rough you can spray a little carb cleaner into oil fill cap and see if idle smoothes out, this is a quick test for leaking intake internally. Get back to us
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Tuesday, March 11th, 2008 AT 7:29 AM
Tiny
BSWINEY
  • MEMBER
Actually, after I had the engine light reset the car has been running pretty smooth. I have put several hundred miles on it and the engine light has not come back on. Just the oil light is giving me problems and lower mpg. When I drive 50 or so miles and the engine heats up and I stop, the engine light will flicker or stay on until I speed the motor up. The mpg is still down about 4 mpg from normal.

I did spray the carb cleaner into the oil fill cap when I thought it was runner a little rough and the engine seem to bog down like it was flooding out but then smoothed out.
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Friday, March 14th, 2008 AT 7:13 PM
Tiny
MASTERTECHTIM
  • MEMBER
I would have the lower intake manifold checked for leaks. This could cause both the oil light problem and running problem.
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Saturday, March 15th, 2008 AT 6:05 AM
Tiny
BSWINEY
  • MEMBER
Thanks.
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Saturday, March 15th, 2008 AT 9:07 AM

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