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I miss carburetors

1997 Cheyenne SWB 4.3L V6 automatic 73,xxx miles bone stock, except for KN airfilter.

Lately the pickup has developed an idle problem. Now it's at a point where I can't keep the engine running with the tranny in drive at a dead stop. Rolling down the road, all is basically well. There's some pinging if I stomp on the gas, but that's it. But I'm in trouble if I stop. Here's why I miss carbs. With a carb, I could pull it off, clean it, adjust it, and the universe would be in harmony again. Not with this TBI. My first thought was to adjust the idle, thinking that maybe the idle adjustment screw vibrated loose. According to Chilton's, the idle speed is stated on a sticker under the hood. The sticker under the hood says it is electronically regulated, and cannot be manually altered. There is a part called an "idle air control valve" that, when tested according to Chiltons, appears good. I also noticed the inside of the TB is covered in a black film that naturally reeks of gasoline. Is that normal for a TB? Is there anything else I should be checking?

Thanks, Charles

I know I'm not a regular here, but advice is appreciated.

Reply to
mad scientist
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That black film is oil from that K&N filter mixed with gas vapor. It is one of the reasons why GM and others are starting to void warrantees on vehicles that have them installed.

Buy some GOOD spray carb cleaner and a toothbrush and clean the TBI real good. Then run some Techron cleaner through it. Also pull your EGR valve off and clean it out since it probably has carbon that is blocking it open enough to effect the idle. Very common with the 4.3.

Reply to
Steve W.

Sounds like the EGR valve is stuck open..perhaps a cleaning as already suggested is in order

Reply to
Eightupman

How do you recommend I clean the EGR? I don't see a way to dismantle it. I did spray some B12 Chemtool down into it several times. Gave it a good shaking, and each time had a fair amount of C come out. Is there something more I need to do to clean it?

Thanks, Charles

Steve W. wrote:

Reply to
mad scientist

Basically pull it off the engine. Hold the pintle open and use a wire to poke around the pintle and break up the carbon. Then use some good carb cleaner to flush the crud out. I also use a stiff pipe cleaner to get the loose stuff. Clean the port in the intake as well. There is a screened gasket available for the 4.3 that will stop the carbon chunks from sticking the pintle open. I recommend it very much.

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makes a good one.

Reply to
Steve W.

Cleaning the TB and EGR may work but it is more likely the MAF sensor. This is a common problem with KN. A little over oil and the MAF sensor gets coated and doesn't read the correct air flow. Hell clean everything can't hurt. If EGR was stuck you would have a service engine light.

Reply to
calhoun

Just for the record: I do NOT miss carburetors.

Reply to
Shoe Salesman

I'll look at that, too. There's been no service engine light.

Thanks, Charles

Reply to
mad scientist

sensor. This

Depends on how far open it is. I have had a couple open just enough to cause a vac leak that didn't set a code.

Reply to
Steve W.

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