Chatter when cold 302

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Dec 13, 2003 | 10:55 AM

White97

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From: Pittsburgh, PA

Chatter when cold 302

97 Explorer V8 302, 40K miles

Just replaced:
Plugs, wires, 2 OX2 sensors
has K&N Intake

Took off Throttle body and cleaned it and IAS by pass valve.
Chatter sound when cold or under load , does not sound like a lifter. Use 89 octane. Once truck is warmed up noise goes away. I think what ever is causing the noise is what killed an upstream and downstream OX2 sensor. Car is garage kept, so cold start up is not that cold.

Sounds more like a clogged something or other. ERG passes vacuum test.

Wife's car, she drives maybe 3 miles a day, could be carbon? I told her a cat-back would fix it!

Any help would be appreciated.

Thanks.

Dec 13, 2003 | 12:00 PM

f100guy

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From: shepherd

cats may be stopped up

Dec 15, 2003 | 09:09 AM

White97

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From: Pittsburgh, PA

Any way of testing the cats?

Dec 15, 2003 | 03:12 PM

f100guy

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From: shepherd

after driving for a good while look under the truck to see if the cat is glowing. but the best way is to take it to the exhaust shop and have them look at it

Dec 15, 2003 | 07:16 PM

3broncocrazy

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From: South Ga

is it only happening @ start-up? could it be dry start - what type oil filter you running.
I'm going out on a limb here, and thinking out loud, this is after you get your new exhaust system of course

Dec 16, 2003 | 06:26 AM

White97

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From: Pittsburgh, PA

One additional fact. I've begun smelling unburnt gas when she pulls it into the garage and turns it off. I change oil every 3000 miles, fram oil filter, castrol 5w30.

I plan on adding the Gibson exhaust.

Once warmed up the thing runs great, gas mileage which was never a strong point seems about the same, no other problems. Engine temp, oil temp all normal.

When I took off the throttle body and cleaned it and the IAC valve I noticed a lot of black soot back near the EGR, but a vacuum test seems to indicate that it is good.

Both the Ford Garage and an independent who does my state inspections think that it is carbon.

Dec 16, 2003 | 03:52 PM

screwy

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From: Over Yonder, MN

Try changing your oil filter to a motorcraft or pure one. Frams are no good. Friend had a similar problem with his 4.0, I tracked it to the fram, it was to constrictive. Good cheap idea.