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Sep 8, 2003 | 10:32 AM

bcwebb

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Joined: Sep 2003

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engine ping

Need help.

I am at a loss. I have had an engine ping ever since the mass air flow sensor was replaced. Since they couldn't find anything else wrong--major tune-up of plugs, wires, cap, throttle body and engine cleaned of carbon--they have replaced the mass air flow sensor thinking it was defective. No go. It still pings and I am having to burn high test. This is a 93 Explore 2WD V6 with 200,000 miles. Where do I look next?

I've also noticed a hum at 60mph and over. I've rotated tires and put it in neutral and it is still present. I have noticed it is louder when turning right slightly and goes away turning left slightly. Do I have a wheel bearing going bad? THis is a standard transmission.

Sep 9, 2003 | 06:33 PM

maa139

Posting Guru

Joined: Apr 2003

Posts: 1,085

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From: West Chester PA

engine ping

Have you checked to see if it is throwing any codes? The DPFE (if it has one) or the EGR valve can cause pings. You don't need a scan tool. You can just use a paperclip and watch the CEL flashing to read the codes...The Haynes manual should have the procedures, or there are threads here that explain it very well.

Sep 9, 2003 | 10:40 PM

c96drumm

Laughing Gas

Joined: Mar 2003

Posts: 877

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From: Colorado, U.S.A!

engine ping

On the hum, I would agree with you that a wheel bearing is probably it, due to the side to side variance.

Sep 9, 2003 | 11:16 PM

mrshorty

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Joined: Dec 2001

Posts: 3,742

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From: UT

engine ping

You've missed one common cause of ping on the 4.0 L OHV, a vacuum leak. Make sure all there are no vacuum leaks. One common vacuum leak is through the lower intake manifold. For some reason, the lower intake manifold bolts come loose over time. Try tightening them. Usually that will fix it. If not, you may need a new lower intake manifold gasket.