GMC Truck Hesitation TBI problems

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GMC Truck Hesitation TBI problems

Unread post by Logo » Fri Feb 05, 2010 10:35 pm

1991 GMC 1500, TBI 350, 700r4 trans, 4wd. Replaced plugs,wires,cap,button,ignition coil, and pcv valve less than 4 months ago to get rid of hesitation and stumble. Now, the problem is back and is worse than it was before. i have heard that an egr valve may be the problem. do you have any ideas of where to start or how to diagnose the problem?

paulKip

Re: GMC Truck Hesitation TBI problems

Unread post by paulKip » Sat Feb 06, 2010 2:11 am

Ya, could be an EGR problem.
Remove it, blow out the passages and the the valve. Then take for a drive to see if that helped. Also use a vacuum pump to see if it actually moves.
Being 20 years old, may be full of carbon.

scotty
Posts: 19
Joined: Sun Oct 14, 2012 11:52 am

Re: GMC Truck Hesitation TBI problems

Unread post by scotty » Thu Feb 21, 2013 9:26 am

Get your fingers under the egr valve. Rev the engine a few times to feel if the diaphram moves. If it seems to be irratic, try unplugging the vaccum hose. If it still moves with the engine speed, the valve is bad. That is because it should not operate with the vacuum hose off.

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