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1LowToy · 02-19-2011, 10:00 PM

There is an idle mixture screw on the base plate. It may have a tamper resistent cover over it. If it's still covered you may wanna rebulild it, as it is over 25 years old. Turn the screw in until idle speed drops by about 50 to 75 rpm. You may need a special socket to fit it as it was designed not to be messed with.

What year model is your truck?

02-19-2011, 10:00 PM	#12
1LowToy Registered User Join Date: Nov 2009 Location: Sonora California Posts: 860	Re: Hard shut off on 4.1l engine There is an idle mixture screw on the base plate. It may have a tamper resistent cover over it. If it's still covered you may wanna rebulild it, as it is over 25 years old. Turn the screw in until idle speed drops by about 50 to 75 rpm. You may need a special socket to fit it as it was designed not to be messed with. What year model is your truck? Last edited by 1LowToy; 02-19-2011 at 10:00 PM.