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post #1 of (permalink) Old 09-19-2005, 04:08 PM Thread Starter
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TBI 350 idle problems??

My dads '89 Suburban has 80,000 mile on engine and we did a 3" lift, 4.56 gears/rear locker, TBI spacer, exhaust, 33/10.50 ProComp ATs, regeared transfercase speedo. More and more lately after startup the engine will idle erradically and bounce from 500-900 rpm and once in a while it dies. Once you start driving it goes away. Usually happens when starting hot. Any ideas??
Thanks much in advance! [img]/ubbthreads/images/graemlins/cussing.gif[/img] [img]/ubbthreads/images/graemlins/scs.gif[/img]
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post #2 of (permalink) Old 09-24-2005, 05:45 PM
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Re: TBI 350 idle problems??

I'd lean towards either fuel pump or MAP sensor.
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post #3 of (permalink) Old 09-28-2005, 12:01 PM
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Re: TBI 350 idle problems??

i just fixed that exact same problem with my chevy. take off the distributor and see if the rotor has any slop in it. if it does then replace the distributor. my truck would idle and sputter and cough and gag and then die. it frustrated me for awhile. i would check the dist. first then plugs and wires and fuel filter. good luck
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post #4 of (permalink) Old 11-28-2005, 02:43 PM
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Re: TBI 350 idle problems??

I'm surpised than nobody said it's your tires.

Vacuum leak - worse at idle and when hot. Possibly the gaskets on the spacer.
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post #5 of (permalink) Old 11-29-2005, 08:44 AM
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Re: TBI 350 idle problems??

Here's my two cents... I believe your Chevy has an EGR valve on the intake manifold behind the TBI? It has a vaccum hose going to it, unplug the hose from the valve and plug it with a golf tee or something. Lightly tap the EGR valve with a hammer to make sure it's not stuck in the open position. If it runs okay after doing this then you can just leave it disconnected or replace the valve. If you don't replace the valve you may have issues with passing emissions testing if the state your in tests for that.
Best of luck...
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post #6 of (permalink) Old 12-04-2005, 09:46 PM
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Re: TBI 350 idle problems??

TPS sensor.

They are under $20 and about a 5 minute install. it is located on the even numbered side of the motor (2 4 6 8) on the side of the tbi. for what ever reason the screws that hold them in are not that strong, so be careful removing the sensor. i had one of the screws break off in the casting of the TBI, so don't force anything.
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