Car suddenly has started to idle at 2500 to 3000 rpms. When it normally was running around 1500 rpms. I don't know what the problem is or what to do so any help or advice would be appreciated!

Also what model Holley carburetor is on my 1986 GT Poniac Fiero 2.6, if it was installed as original equipment?

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Andrew Draucker

Stock Fiero? It's not a carburetor....it's a throttle body. Your change in idle speed is a vacuum leak.

Your problem is most likely a cracked Intake manifold to EGR tube. To test loosen the two bolts at the bottom of the intake manifold snout that attach the insulated tube to the intake. Cut a strip of aluminum can the width of the UPC symbol. Slip it in between the tube and the intake. Tighten the bolts and see if the trouble goes away. If so it is cracked. The intake manifold to EGR tube can be repaired with brazing. It is a pita to take off and put back on. You can't see the cracks until you take off the insulation.

The bolt heads on the bottom of the intake have 10mm heads.

ALL 2.8 Fieros have a throttle body that says HOLLEY on the top of it.

[This message has been edited by phonedawgz (edited 08-24-2013).]

On my 87 Fiero GT 2.8 , I have a high idle also and put the aluminum in as stated but no help, could it be the idle control valve. The reason I ask is because if I remove it and block it with my finger then the idle drops to around 900-1000 rpms.

quote Originally posted by Drewdrauck6: Car suddenly has started to idle at 2500 to 3000 rpms. When it normally was running around 1500 rpms. I don't know what the problem is or what to do so any help or advice would be appreciated! Also what model Holley carburetor is on my 1986 GT Poniac Fiero 2.6, if it was installed as original equipment?

there is no carb o the Fiero's, not on any of them, the Holley you see there on the drivers side of the engine is the throttle body. no fuel runs threw there, just air.

there is no throttle adjustment like there is on a carb. think vacuum leak somewhere, anywhere. I use starter fluid but in you case I would use water in a spray bottle to check for vacuum leeks. start there and get back to us, or get a cheap service manual, Haines sucks but its better than nothing at least it tells you they are fuel injected and not carbureted.
when ever I buy another vehicle I always buy a manual just for that vehicle, no matter how cheap it is, the manual, its better than nothing.
Steve

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Technology is great when it works,
and one big pain in the ass when it doesn't



Detroit iron rules all the rest are just toys.

quote Originally posted by NiotaFiero: On my 87 Fiero GT 2.8 , I have a high idle also and put the aluminum in as stated but no help, could it be the idle control valve. The reason I ask is because if I remove it and block it with my finger then the idle drops to around 900-1000 rpms.

That tells you that you have a vacuum leak somewhere else. Check your brake booster line or the short tube under the throttle body.

quote Originally posted by Drewdrauck6: Car suddenly has started to idle at 2500 to 3000 rpms. When it normally was running around 1500 rpms. I don't know what the problem is or what to do so any help or advice would be appreciated! Also what model Holley carburetor is on my 1986 GT Poniac Fiero 2.6, if it was installed as original equipment?

OK, if you say you have a Holley carb, I'll believe you and no, it is not stock, If it is a carb doing that, 90% chance the base plate gasket on the carb is your vacuum leak,

Spray some WD40 around the seam and see if the idle changes. Also check your vacuum tubes, the brake booster (the big one) as well as the PCV line. If your distributor has a vacuum advance, check that vacuum line. Wirh a carb it is straight forward. The idle is normally stable and you need a Holley carb performance book to adjust it

Hope this helps

Arn

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