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Stalling when slowing down, stopping slowly

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Old 03-11-2008, 10:06 PM
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Default Stalling when slowing down, stopping slowly

if I stop quickly it acts normal, but if I slow up to almost a complete stop, or I do stop, the thing acts like it wants to stall and I'll tap the gas to save it, or it'll trick me and stall anyways. It's not just shutting off, it's sputtering out. it's a 1990 TBI 350 with a 1" spacer, 1/4" injector spacer, ahigh-rise alum. intake, and this is mated to a 700R4 trans [which I might dump for a stickshift soon]. I changed the FPS, TPS, did a tune-up, andthe MAP and injectorsare 2 years old. I fear the front intake gasket has a leak, but I don't hear or feel anything no matter if it's cold or warm. it also takes about5-10 seconds of cranking to start. I know there's something I overlooked, because I do that quite a lot. Any iders?
 
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Old 03-11-2008, 10:29 PM
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Default RE: Stalling when slowing down, stopping slowly

You can use carb cleaner as a way of determining if you have a vacuum leak. Just spray it around the suspected areas and listen for a change in the idle speed. An unlit propane torch works as well. I would start at the TBI base gasket between the TB and the spacer as well as the spacer and the intake. On a stock motor, this is known to be a problem area.

Do you have a functioning EGR system? If you do, then it could be a stuck EGR valve...
 
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Old 03-11-2008, 10:44 PM
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Default RE: Stalling when slowing down, stopping slowly

Actually, I just changed the gasket between the intake and spacer because it blew out on both sides, and about 4 months back I completely rebuilt the throttle body, just because of the FPRI forgot to mention the EGR, which is also 2 years old.

Thanks, I'll try that trick you said with the carb and choke cleaner. I also seem to have no power in overdrive, if that has anything to do with it... I rarely or never use overdrive anyways, because I can go 80 at 2,600 RPM in drive as it is with no issues.
 
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Old 03-11-2008, 11:20 PM
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Default RE: Stalling when slowing down, stopping slowly

Kyle has some good info there.
I would also suggest a fuel pressure test. You can change your fuel filter, empty the old one through a white cloth and tap it to see if there is anything in the filter. If you see the colour black, it's an indication the the fuel pump is wearing out.
 
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Old 03-12-2008, 01:47 AM
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Default RE: Stalling when slowing down, stopping slowly

Actually, two years ago my buddy[who owned it at the time] put in a pump, and about 6 months ago I changed the filter, butbrownish-black stuff came out of the old filter. I can't remember if he said it was a high-output or not, though.
The pump won't be too hard to change though, because we cut an access panel in the floor back there, mainly because the floors need replaced as it is.
 
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