A Question About A Problem My GMC Is Having... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Narkoleptik · 03-25-2003, 10:29 AM

Ok, for the last couple of days, my truck has been having a rough time taking off at the lights... It used to be that hitting the gas meant that the truck would immediately leave the line and run smoothly... Now, when I step on the gas, (not hard mind you) it takes a few seconds for it to speed up to what it used to be like. It kinda seems to struggle when started at an upward angle (IE a light on an overpass) Almost like it is wanting to shut itself off... MY father says it might be a problem with the fuel pump and I haven't been able to replace it with a new one, was wonder what most of you thought as well? Perhaps Tranny problems? (HOPE NOT)

Thanks in advance for your input.

**nightmare** · 03-25-2003, 10:32 AM

doesn't sound like a tranny problem to me. sounds like it might be the fuel pump, but could be the filter too.

*Randy70C-10* · 03-25-2003, 10:35 AM

Doesn't sound like the tranny. Could be a number of things though. How old are your spark plugs? A fouled plug will definately kill your take-off. Do you have a mechanical pump? Usually a fuel pump either works or it doesn't.

*Randy70C-10* · 03-25-2003, 10:44 AM

Yeah, filter could be a good thing to check to, or maybe there is dirt or a piece of rust clogging a jet. Also, check all of your vacuum lines.

Mongo · 03-25-2003, 11:43 AM

one other thing to check is the gasket under the carb if you have a small leak in the seal it will kill your take off. If the leak in the seal gets too large your truck will run like $hit and wont idle worth a damn. get some carb cleaner and while the truck is running spray it around the base of the carb if the idle changes you have a gaasket leak. also spray it around all vaccuum lines check for any vaccuum leaks.

I went through two fule pumps three fule fliters and half a box of band-aids before I found this leak.

good luck

Longhorn Man · 03-26-2003, 01:09 AM

Start with a tune up. Plugs, wires, cap and rotor, and a fuel filter too.
That's what I'd do anyways from the sounds of your description.

Hooter · 03-26-2003, 03:16 AM

maybe your accelerator pump is goin on the fritz

Chevy Wrench · 03-26-2003, 03:22 AM

Or, you might try adjusting the air/fuel mixture screws. And possibly the diaphram on your acc. pump has started to leak. Just a thought. By the way, I used to live in Tucson, hows the weather? If you need help with it, I could give you the name of a shop I know of that would be able to help you with it. Pretty good bunch of guys. Good luck.
John

spinning wheels · 03-26-2003, 03:25 AM

If the tune-up won't fix the problem. And you don't have a vaccum leak, check the gas sending unit in the gas tank. When I replace mine, the old one was so plugged up, I'm suprised the truck even ran! Good luck.

Blue Beard · 03-26-2003, 08:42 AM

You might also replace the rubber fuel lines.......both at the tank, and the engine. If these are old they can create the same type of effects.

03-25-2003, 10:29 AM	#1
Narkoleptik 69 GMC LWB FLEET Join Date: May 2002 Location: Tucson, Az, USA Posts: 108	A Question About A Problem My GMC Is Having... Ok, for the last couple of days, my truck has been having a rough time taking off at the lights... It used to be that hitting the gas meant that the truck would immediately leave the line and run smoothly... Now, when I step on the gas, (not hard mind you) it takes a few seconds for it to speed up to what it used to be like. It kinda seems to struggle when started at an upward angle (IE a light on an overpass) Almost like it is wanting to shut itself off... MY father says it might be a problem with the fuel pump and I haven't been able to replace it with a new one, was wonder what most of you thought as well? Perhaps Tranny problems? (HOPE NOT) Thanks in advance for your input. __________________ TUCSON, AZ

03-25-2003, 10:35 AM	#3
Randy70C-10 Account Suspended Join Date: Mar 2001 Location: Virginia Beach, Va. U.S.A. Posts: 15,320	Doesn't sound like the tranny. Could be a number of things though. How old are your spark plugs? A fouled plug will definately kill your take-off. Do you have a mechanical pump? Usually a fuel pump either works or it doesn't. Last edited by Randy70C-10; 03-25-2003 at 10:42 AM.

03-25-2003, 11:43 AM	#5
Mongo YES_____NO Join Date: Jul 1999 Location: Somewhere in the vicinity of betelgeuse Posts: 7,351	one other thing to check is the gasket under the carb if you have a small leak in the seal it will kill your take off. If the leak in the seal gets too large your truck will run like $hit and wont idle worth a damn. get some carb cleaner and while the truck is running spray it around the base of the carb if the idle changes you have a gaasket leak. also spray it around all vaccuum lines check for any vaccuum leaks. I went through two fule pumps three fule fliters and half a box of band-aids before I found this leak. good luck __________________ People many not remember what you said or what you did, but they will remember the way you made them feel. - unknown Cause, remember: no matter where you go... there you are. - Buckaroo Banzai 1984 Help support the board

03-26-2003, 03:16 AM	#7
Hooter My other Love Join Date: Aug 2001 Location: Castlegar B.C. Canada Posts: 4,085	maybe your accelerator pump is goin on the fritz __________________ Castlegar B.C.The great white North (Canada Eh!) Hooter_5@hotmail.com First generation Monte Carlo club pictures of my life

03-26-2003, 03:22 AM	#8
Chevy Wrench former desert rat Join Date: Feb 2003 Location: salt lake city, utah Home of the 3 M's Mormons, methlabs and minivans Posts: 320	Or, you might try adjusting the air/fuel mixture screws. And possibly the diaphram on your acc. pump has started to leak. Just a thought. By the way, I used to live in Tucson, hows the weather? If you need help with it, I could give you the name of a shop I know of that would be able to help you with it. Pretty good bunch of guys. Good luck. John __________________ 94 Chevy Silverado Ext cab 4/6 drop w/ 18's and 2500watt system (work truck). 67 Chevy swb under const. frame off custom, 20's, bagged and a large rat under the hood,and a 1940 Chevy truck under const.

03-25-2003, 10:44 AM	#4
Randy70C-10 Account Suspended Join Date: Mar 2001 Location: Virginia Beach, Va. U.S.A. Posts: 15,320	Yeah, filter could be a good thing to check to, or maybe there is dirt or a piece of rust clogging a jet. Also, check all of your vacuum lines.

03-26-2003, 01:09 AM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Start with a tune up. Plugs, wires, cap and rotor, and a fuel filter too. That's what I'd do anyways from the sounds of your description.

03-26-2003, 03:25 AM	#9
spinning wheels Registered User Join Date: Sep 2001 Location: Hacienda Heights, California USA Posts: 474	If the tune-up won't fix the problem. And you don't have a vaccum leak, check the gas sending unit in the gas tank. When I replace mine, the old one was so plugged up, I'm suprised the truck even ran! Good luck. __________________ '72 GMC custom camper 350/350

03-26-2003, 08:42 AM	#10
Blue Beard Registered User Join Date: Jan 2003 Location: Washington State Posts: 8,831	You might also replace the rubber fuel lines.......both at the tank, and the engine. If these are old they can create the same type of effects. __________________ 1970 Chev CST 2003 Harley Fatboy 1975 Chevrolet Step Van 1956 Chev Bel Air 1977 Blazer 2WD For Sale $3000.00 1978 Blazer 2WD For Sale $7000.00 1978 Silverado 2005 Monte Carlo



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.