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My son has a 2000 Mustang 3.8
144,000 miles.
Just after start up it idles higher than it should and runs rougher than it should The plugs on the back 2 cylinders (5 &6) I believe appear oil or fuel fouled and had what I thought was coolant I did a compression test and all cyls were nearly equal. I have replaced: Plugs and wires, intake gaskets,valve seals thinking they might be leaking and dumping coolant into cyl #6.and or a vacuum leak.completely cleaned the intake and throttle body.
Replaced both up stream O2 sensors as the left one failed and was white in color
Any idea what is causing this?
I am thinking it maybe a leaking injector?
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Start with checking for vacuum leaks. This will cause a higher idle.
Do the new plugs look as fouled as the old?http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
That really sounds like a vacuum leak to me.
When you first start it up, what does the engine sound like? Does it wind up, then come back down and idle rough or does it just start and immediately have the rough idle?Yes, the new plugs get gummed up pretty quick.
The thing is it is not burning any oil, I thought it might be burning coolant,but after replacing the valve seals it no longer has any smoke on start up.
I will check again for vacuum leaks this weekendNo,
It is just constant idle
It’s acts like the idle is set to high.
I cleaned the IAC and the EGR valves and tubes ppI have been looking for a vacuum for awhile and this one is hard to find.
Any idea as to why the 2 plugs on 5 & 6 are the only ones getting build up?
The other 4 look great?I’m not knowledge enough to know this, but I’m guessing a compression test doesn’t test spark plug health accurately. The IACV doesn’t really stick during warmer temps unless you’re unlucky. Did you take it out completely and clean/oil it the proper way? Another thing I was thinking of is replacing the fuel filter.
[quote=”SAJ” post=168072]I have been looking for a vacuum for awhile and this one is hard to find.
Any idea as to why the 2 plugs on 5 & 6 are the only ones getting build up?
The other 4 look great?[/quote]If the two plugs are looking fouled already then most likely its oil loading on there.
see if this helps with reading plugs.
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