92 astro idle rough, surging, backfiring

92 astro idle rough, surging, backfiring

Postby compfreak [OP] » October 6th 2008, 3:50am

I just got a 92 astro van from my dad and while idling it vibrates the whole van very badly. enough to give me a headache. while driving if i hold it at a steady throttle i can feel the van surge pretty badly, also while going up steep inclines it backfires out of the intake.. its a TBI i believe, i just changed the fuel filter i was told the spark plugs were changed less then a year ago. it sat for about 3 years. before that it ran and idled fine but still backfired. its the v6 and has 130k miles i dont know anything about these vans, any help would be very much appreciated
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Re: 92 astro idle rough, surging, backfiring

Postby gtkane » October 7th 2008, 3:27am

There are a number of things that it could be.
1. vac leak. The gasket under the throttle body is known to crack,causing a leak, and will give those symptoms.(usually has high idle as well)
2. Corrosion in the cap and rotor. Causes misfiring and surging.
3. EGR valve stuck open. Carbon plugs it up.
4. Low fuel pressure. Could be caused by weak fuel pump, or by a faulty fuel pressure regulator.

I would check these in this order first.
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Re: 92 astro idle rough, surging, backfiring

Postby compfreak [OP] » October 7th 2008, 7:06am

What is the best way to change the gasket on the thottle body? just pull the cover inside and go from there? also where might the egr be located?
Original Poster [OP]
compfreak
Fueling (1/8 tank)
Fueling (1/8 tank)
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Re: 92 astro idle rough, surging, backfiring

Postby Gary » October 7th 2008, 11:38am

Go with delco cap and rotor first.Do delco wires as well.Do that before you do anything else.Tell us how you made out then.
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