1991 Other Isuzu Models bad idle on start

1991 ISUZU
171,729 MILES • 4 CYL • 4WD • MANUAL
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TONY_JKLH
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  • 1 POST
my isuzu has a 2.6L engine. i can start it when it hasnt beed driven for 4 hours without problems. but when i start it within that time it will start and baraly run. it idles extremaly bad shaking the whole truck. but after you drive it for 5 minuts it clears up and runs good. until you turn it off and start it again. i have changed the temp sensor, mas sensor, fuel injectors, idle solonoid. ecm module, and checked the fuel presure, changed spark plugs, checked timing, and still wont run better. and all the gaskets are good(intake manifold, throttle body, i-tec)please help me. thanks
Mar 13, 2008 at 4:58 PM
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MHPAUTOS
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  • 31,937 POSTS
  • ASE Certified Mechanic
Check for any set fault codes first, the light does not have to be on for a fault to be set. I would re check standing fuel pressure, hook up gauge and run engine, note pressure, check every 1/4 HR and see how much pressure has dropped, if to low after 1/2 hr you may have a leaky pressure regulator or a faulty pump valve (leaking back) check this first

mark (mhpautos)
Mar 17, 2008 at 3:30 AM
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