93 dodge van; 360 auto

[regis]

There is detonation(pinging). I bought this used and don't
know what work has been done. Cleaned the IAC or is it
ISC?(right behing the Throttle at the butterflies. Was more
souty than dirty and looking down into the pendulum;
it looked aok. Checked the throttle sensor and seemed
ok. 83000 orginal miles.

Before I go into the engine; what would be the mail curprit
causing the pinging? The battery terminals were dirty and
when I cleaned the posts the pinging stop while speeding up
on the level but still pings? climbing hills.

[Dodgevanman]

One thing that may cause exessive pinging is a stuck EGR valve...could be stuck open or closed. Another more serious cause could be the intake plenum gasket has failed. You will also notice mysterious oil consumption as well if this gasket has failed. It's pretty common on the Magnum engines. I had to do this repair to my '94 van a couple of years ago.

[alloro]

How long was the van sitting when you bought it? Old gas loses it's octane and will ping like crazy. If it was sitting for a while, run the tank down and give it some fresh gas. A bottle of dry gas when you add the fuel wouldn't be a bad idea either.

[regis]

I rule out igr because a higher test of gas was used
and took out the pinging. But this van has been
able to use the low grade before so something
happened?

What to look for? It starts, runs, idles, well but
BIG drop in gas milage? :help:

[alloro]

Start hunting for a vacuum leak.

[DANVAN]

Clogged cat converter?