unexpected engine revving--going to kill someone!!

This is a 1992 4.3 vortec and I just got the thing. It's in a Bravada which is totally irrelevant but while warming it up for the first time the dash which is fully electronic display suddenly got brighter and the engine revved up for about five seconds and then went back to normal. While driving it I stopped along the road and while sitting idling in gear the thing did it again. This is a kill someone problem and I hope someone has the solution. It's a little scary.

How many RPM's does it go to.
Have you cheked for codes?
Any check engine lights on?

Mine did that when the CPI fuel regulator was leaking AND AFTER you stepped on the brake, when the power brake diaphram was resetting(for lack of a better term).

I wonder if Eric's ever did that?

I didn't note the RPM and I can't read the codes until I get the darn thing on the road again. While servicing the tranny I broke a bolt pulling the exhaust down and now am having to pull the drivers side exhaust manifold. I think the brakes may have something to do with it because the anti-lock light is coming on. I'm also thinking maybe a problem with the cruise control. I'll get you guys more info once I have it running again.

I got this thing running again so It's time to bring it back to the top. It hasn't done the rev thing for a while so that is obviously an intermittent problem. The other things:

1. The oil pressure is up to 80 and down to zero and it may be doing this more when it's shifted but it's almost constant.
2. The engine stalls when put in any gear unless the engine is held at 1000 rpm, and if you just move the shifter slightly towards reverse the engine grunts and loses rpms.
3. The engine will occasionally quit and not restart for hours or overnight.
4. The service engine light does come on occasionally and I will get a read on that possibly tonight if this reader I have now works.
5. the anti-lock brake light comes on occasionally. (probably unrelated but not ruling it out)

Question: Would a short somewhere in the column cause these problems?

The transmission has been serviced with added seafoam treatment and the oil changed. I changed the fuel filter. The exhaust is all new except for the converter.

Post back codes.

Is the egr valve sticking open?

Just a little hint on the exhaust bolts.......leave them alone. Use a sawzall and cut the pipes in a place where it can be welded back together easily. The muffler shop guy said he does all of the transmission shops re-welding.

Post back codes.

Is the egr valve sticking open?

I pulled the EGR and it would stick open when pushed all the way open. I cleaned the gunk out and performed the electrical test and all is now good, but I have to wait about a week to get a new gasket. I either have to wait for parts for a week or the internet goes down for a week so thanks in advance for being so patient on this.

You are welcome and thanks for posting back how it is going.

OK I figured out how to read codes on this thing. I didn't know you could do it without a reader but anyway I got a code 53 so I guess the alternator is shot or does anyone have another Idea. This might explain a lot of the strange problems I'm having.

OK I figured out how to read codes on this thing. I didn't know you could do it without a reader but anyway I got a code 53 so I guess the alternator is shot or does anyone have another Idea. This might explain a lot of the strange problems I'm having.


Get the charging system voltage checked out.
Battery and battery cables and grounds wiring can affect voltage to.
Code 53 is a overcharging voltage problem.
But always clear code and see if it returns.
Get us know how it goes.