1989 CRAZY TACH, THUMPING AT INTAKE

P-ROY · #1 (**permalink**) 11-02-2009, 11:19 AM

Good day,

My 1989 F-250 7.3, manual trans., 200,000 miles, idles quite roughly at times.

When it does, there is a rumbling/thumping at the intake and my tach needle wavers/revs erratically.

I dread a valve repair this close to winter.

Any thoughts on how to diagnose this problem or what I should look for would
be greatly appreciated.

Pat from Montreal

PLC7.3 · #2 (**permalink**) 11-02-2009, 01:02 PM

Warm engine compression test, visual on valve rocker assy operation/wear.

Valve guide sideways slop with valve stem depressed 1/4".........