Engine runs rough, no mil, no miss fire

Tiny
SHELLY77
  • MEMBER
  • 1998 MERCURY VILLAGER
  • 102,000 MILES
Engine runs rough at idle, no loss of power, no vaccum leaks checked fuel. Pressure spark timing at the balancer, checked the fuel Injectors. Came to the conclusion that the timing belt must have jumped a tooth its never been replaced
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Monday, May 7th, 2012 AT 9:28 PM

11 Replies

Tiny
DRCRANKNWRENCH
  • EXPERT
Here is a diagnostic walk through for your situation. Just use the link below to get to it;

http://www.2carpros.com/articles/engine-misfires-or-runs-rough
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Monday, May 7th, 2012 AT 9:33 PM
Tiny
SHELLY77
  • MEMBER
I've already gone through the testing, and there is NO miss fire. Everything comes out ok, doesn't feel bad under a load, no loss of power, and it doesn't die out, the fuel pressure is at factory specs, spark plugs are fairly new along with the wires, cap and rotor.
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Monday, May 7th, 2012 AT 10:11 PM
Tiny
HMAC300
  • EXPERT
Check for a vacuum leak and clean throttleplateon both sides
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Monday, May 7th, 2012 AT 10:18 PM
Tiny
SHELLY77
  • MEMBER
Already checked vaccum, no leaks and cleaned the throttle plate. Any other ideas besides what I've already posted?
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Monday, May 7th, 2012 AT 10:31 PM
Tiny
HMAC300
  • EXPERT
Di you use a spray like choke cleaner to check for leaks or how did you doit. If you have checked everything than check compression then check to see if your wires are in teh correct firing order. Then pressure check your engine for a head/intake gasket leak.
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Monday, May 7th, 2012 AT 10:33 PM
Tiny
SHELLY77
  • MEMBER
I used choke/throttle plate cleaner to check for leaks after visual inspection, that was one of the first things I did. The wires are in order. Is it NOT possible that the belt jumped a tooth, or am I just chasing my tail here? No mil, no miss fire, no vaccum leak, egr was clean, thottlebody was clean. If there was a vaccum leak affecting it like this I would have at least a lean code, if the compression was an issue I would have a miss code most likely a P0300. I don't know I'm lost here.
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Tuesday, May 8th, 2012 AT 12:17 AM
Tiny
ASEMASTER6371
  • EXPERT
If the belt jumped a tooth as you think, it would start hard. It would not crank right up and you would have power loss due to timing change.

Are you sure the roughness at idle is not a bad motor mount?

Roy
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Tuesday, May 8th, 2012 AT 12:32 AM
Tiny
SHELLY77
  • MEMBER
See that's a good point, thank you it starts relatively easy and it drives pretty well I never thought a motor mount, I'm going to check tba later
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Tuesday, May 8th, 2012 AT 1:05 AM
Tiny
ASEMASTER6371
  • EXPERT
Remember, we are all trying to help. We dont know anyone we help and we always ask basic question first before going out of the box. Be patient, we have a tremendous amount of talent helping here all with the same goal.

Roy
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Tuesday, May 8th, 2012 AT 1:12 AM
Tiny
SHELLY77
  • MEMBER
Well I have to say thank you I've been a mechanic for over 15 years and this is the first time I've ever been on a site like this it's a friends car and I guess I gt a little aggravated it's rare I get stumped like that if I came off rude to anyone I do have to apologize thank you to everyone for your suggestions and idea thank you for steering me in the right direction
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Tuesday, May 8th, 2012 AT 4:35 AM
Tiny
ASEMASTER6371
  • EXPERT
Good luck

Roy
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Tuesday, May 8th, 2012 AT 10:24 AM

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