High speed ping

When passing slower moving vehicles on two lane roads or up hills my 94
XLT with 170K miles begins to ping above 70 mph until I lift my foot. I
have done the following with no permanent fix:
Replace fuel pressure regulator; replace ignition wires; replaced upper
intake manifold gaskets;change to platinum plugs; used mid grade gas;
cleaned the MAF twice a year; replaced oxygen sensors; and installed K&N
air filter.

If anyone has had similar symptoms and found a permanent fix I would
love to hear about it.

Rhys Pieces wrote:
> When passing slower moving vehicles on two lane roads or up hills my 94
> XLT with 170K miles begins to ping above 70 mph until I lift my foot. I
> have done the following with no permanent fix:
> Replace fuel pressure regulator; replace ignition wires; replaced upper
> intake manifold gaskets;change to platinum plugs; used mid grade gas;
> cleaned the MAF twice a year; replaced oxygen sensors; and installed K&N
> air filter.
>
> If anyone has had similar symptoms and found a permanent fix I would
> love to hear about it.

I have a '92 XLT 4.0 that did the same thing when I first bought it
three years ago. I switched from regular to mid-grade fuel and it
stopped pinging. But, then I started reading how mid-grade fuel will
eventually cause other issues so I looked for another answer. On the
advice of a local mechanic I re-torqued the head bolts (not the intake
manifold bolts) which were mostly all below spec for tightness. I've
went back to regular fuel and it hasn't pinged since, even going up
hill and accelerating hard.

You didn't mention if the head bolts were checked when you had the
other work done, but if not, I'd say it's your next move. You'll need
every kind of socket swivel and extension there is to get to them all,
but it can be done . . .

Good luck.

NickD