Odd idle during driving - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ksshane · 10-10-2013, 01:41 PM

I noticed last weekend that my truck started acting as if my foot was on the throttle even when I was stopped at a light with the clutch pushed in.

I had bought a new edelbrock carb a few weeks ago and just never got around to changing it out so I figured this was a sign. Old carb was manual choke (not hooked up) and I wanted to go with a electric choke (Ill hook it up tonight or tomorrow, didnt have time yesterday).

I changed out the carb yesterday, and was planning on driving the truck to work today. Came to my first stop and wouldnt you know it. The exact same thing is happening. Fast idle like I have my foot on the throttle even though one foot is on the clutch and the other is on the brake.

Any ideas? Could it be just because of the weather and I dont have the choke hooked up? Or maybe a vaccuum?

MARKDTN · 10-10-2013, 01:51 PM

Sounds like a leak maybe in the brake booster vacuum.

ksshane · 10-10-2013, 01:58 PM

I replaced the brake booster vacuum line yesterday.... I was in a hurry at that point so Ill double check it.

cleszkie · 10-10-2013, 04:46 PM

Check your throttle cable and make sure it operates smoothly. It may be getting hug up. Also check that your return spring is able to snap the throttle plates closed.

ksshane · 10-11-2013, 08:01 AM

I messed with this and messed with this last night after work. Changed springs several times. Checked the brake booster vacuum hose. Checked the rest of my vacuum hoses. Traced my throttle cable... But everything seemed fine while I was working on it under the hood, but every time I would button it up and drive it... Sure enough... High idle after driving a few blocks.

I also noticed that my throttle seemed really stiff when I would go to drive the truck.

This morning at work a light bulb went off....lol.... Im a moron.

A couple of weeks ago my son saw one of those generic 14 inch air cleaners and wanted it for the truck. He is only 8, but I want him to understand the joy we get out of working on our own vehicles so I bought it and we put it on together.
When I opened the box at home I realized it was one of those drop base air cleaners, but it seemed to fit fine.

I bet my throttle mechinism is hitting the bottom of the base and thats why my throttle feels tight, and then its sticking on the return..... And thats why I only notice it when I drive becaus of course I keep putting the air cleaner back on when I drive it....lol

Ill run home at lunch and test that idea.....lol

10-10-2013, 01:41 PM	#1
ksshane Registered User Join Date: Jul 2013 Location: Wichita Ks Posts: 495	Odd idle during driving I noticed last weekend that my truck started acting as if my foot was on the throttle even when I was stopped at a light with the clutch pushed in. I had bought a new edelbrock carb a few weeks ago and just never got around to changing it out so I figured this was a sign. Old carb was manual choke (not hooked up) and I wanted to go with a electric choke (Ill hook it up tonight or tomorrow, didnt have time yesterday). I changed out the carb yesterday, and was planning on driving the truck to work today. Came to my first stop and wouldnt you know it. The exact same thing is happening. Fast idle like I have my foot on the throttle even though one foot is on the clutch and the other is on the brake. Any ideas? Could it be just because of the weather and I dont have the choke hooked up? Or maybe a vaccuum? __________________ 71 swb 350/4sp manual 5/7 static drop

10-10-2013, 01:51 PM	#2
MARKDTN Registered User Join Date: Jan 2011 Location: Chattanooga, TN Posts: 2,144	Re: Odd idle during driving Sounds like a leak maybe in the brake booster vacuum. __________________ '83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project

10-10-2013, 01:58 PM	#3
ksshane Registered User Join Date: Jul 2013 Location: Wichita Ks Posts: 495	Re: Odd idle during driving I replaced the brake booster vacuum line yesterday.... I was in a hurry at that point so Ill double check it. __________________ 71 swb 350/4sp manual 5/7 static drop

10-10-2013, 04:46 PM	#4
cleszkie Registered User Join Date: Feb 2003 Location: Santa Ana, CA Posts: 2,191	Re: Odd idle during driving Check your throttle cable and make sure it operates smoothly. It may be getting hug up. Also check that your return spring is able to snap the throttle plates closed.

10-11-2013, 08:01 AM	#5
ksshane Registered User Join Date: Jul 2013 Location: Wichita Ks Posts: 495	Re: Odd idle during driving I messed with this and messed with this last night after work. Changed springs several times. Checked the brake booster vacuum hose. Checked the rest of my vacuum hoses. Traced my throttle cable... But everything seemed fine while I was working on it under the hood, but every time I would button it up and drive it... Sure enough... High idle after driving a few blocks. I also noticed that my throttle seemed really stiff when I would go to drive the truck. This morning at work a light bulb went off....lol.... Im a moron. A couple of weeks ago my son saw one of those generic 14 inch air cleaners and wanted it for the truck. He is only 8, but I want him to understand the joy we get out of working on our own vehicles so I bought it and we put it on together. When I opened the box at home I realized it was one of those drop base air cleaners, but it seemed to fit fine. I bet my throttle mechinism is hitting the bottom of the base and thats why my throttle feels tight, and then its sticking on the return..... And thats why I only notice it when I drive becaus of course I keep putting the air cleaner back on when I drive it....lol Ill run home at lunch and test that idea.....lol __________________ 71 swb 350/4sp manual 5/7 static drop



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