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Rough Idle

  • Thread starter Thread starter MCHR
  • Start date Start date Feb 25, 2011
M

MCHR

New Member
Feb 25, 2011
1
0
0
Feb 25, 2011
#1
  • Feb 25, 2011
  • #1
I had my leaking rear main seal replaced as well as a cracked exhaust manifold. They did a complete transmission service while it was out. I have noticed since I got the car back that it idles rough. Its RPMs drop down to about 600 and then pop back up to 800. Is this coincidence or do I need to get something adjusted from the transmission being taken out? What could cause the rough idle?

Just wanted to add when the car is sitting somewhere and idleing at 800 it is smooth and normal, but after sitting for awhile it will drop to 600rpms and that is when it gets a little rough. I plan to get new sparkplugs/wires at my next oil change...after the last garage bill I am a little strapped for cash. I am taking the car in next week so that the mechanic can go over it and make sure everything is going good from the rear seal and exhanust manifold repair.

The car is a 2003 with 86K miles, it has been very well taken care of as I have never skipped an oil change and have done all other forms of maintenance on schedule to the best of my knowledge
 

MustangLX-5.0

Founding Member
Dec 2, 2000
856
7
38
Lehigh Acres Fla.
Mar 1, 2011
#2
  • Mar 1, 2011
  • #2
Rough? Just a little shaking or a lot? 750 RPM is standard idle speed. Is it an automatic or manual? Do you have a Check Engine light? It's possible a sensor was not plugged back in on the transmission on re-install but that 's usually only for automatics. Also, the engine may just need the injectors cleaned or the plugs/wires replaced. Other than that, I can't tell you what the problem is. I don't even know just how "Rough" it is running. Can you provide a little more info?
 
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