88 Burb rough idle at start, gets worse - The 1947 - Present Chevrolet & GMC Truck Message Board Network

kw · 06-10-2005, 12:38 PM

Hey all,

I'm trying to troubleshoot a problem I'm having with my 88 GMC suburban.

When it starts, the idle is rough, when I start to drive it sometimes backfires, but runs rough and seems to lack power. If I romp on the gas it seems to get up and go OK, but when at around 45-55 mph it seems to hesitate and run rough. I checked the plugs and they seem OK. Thinking it might be water in the fuel, I've been running drygas and fuel injection cleaner every tank and still it does it.

I don't have a shop manual for it yet, and was wondring if there is a systematic approach to repair this without replacing every sensor in the vehicle. Any ideas?

The engine is fuel injected and stock. 94k miles.

I was going to start with the fuel filter. Where is it located?

Thanks in advance for any help.

Kurt

aggiedave98 · 06-10-2005, 01:41 PM

it's under the frame rail on the passenger's side about mid-way down the truck.

*bisquik65* · 06-10-2005, 07:51 PM

Take your dist cap off,and rotor ,look at the magnetic pickup on the shaft..(the part with 8 points on it) If its cracked ,then you need a distributer...Very common problem with the TBI engines...And if you get a reman one,look at it good . Make sure the module is new..i bought several of them and an old module on them..I change them all the time...I but its cracked in yours from what you are saying...The dist on these TBI motors controls the injector pulse,if its not right it misses...

Erick

poolcues · 06-10-2005, 11:45 PM

check the injectors.take off the air cleaner,crank the engine and see if the spray pattern coming from the injectors is a conical spray,if not they're easy to replace.

other than that you can run some codes,post them and wait for an answer.

good luck

toroflow · 06-14-2005, 04:18 PM

Also it might be your throttle body to intake manifold gasket. Is the idle faster than normal at idle? If so, you have a bad TB gasket...this seems to be a common problem. Good luck.

*bisquik65* · 06-14-2005, 10:04 PM

Quote:

Originally Posted by poolcues

check the injectors.take off the air cleaner,crank the engine and see if the spray pattern coming from the injectors is a conical spray,if not they're easy to replace.

other than that you can run some codes,post them and wait for an answer.

good luck

Hey there poolcues Where have you been?

kw · 07-27-2005, 01:46 PM

New fuel filter, distributor cap, wires and rotor button, and it's running just fine.

Thanks, everybody for the help.

Kurt

06-10-2005, 12:38 PM	#1
kw Registered User Join Date: Jul 2000 Location: Owings, MD Posts: 119	88 Burb rough idle at start, gets worse Hey all, I'm trying to troubleshoot a problem I'm having with my 88 GMC suburban. When it starts, the idle is rough, when I start to drive it sometimes backfires, but runs rough and seems to lack power. If I romp on the gas it seems to get up and go OK, but when at around 45-55 mph it seems to hesitate and run rough. I checked the plugs and they seem OK. Thinking it might be water in the fuel, I've been running drygas and fuel injection cleaner every tank and still it does it. I don't have a shop manual for it yet, and was wondring if there is a systematic approach to repair this without replacing every sensor in the vehicle. Any ideas? The engine is fuel injected and stock. 94k miles. I was going to start with the fuel filter. Where is it located? Thanks in advance for any help. Kurt

07-27-2005, 01:46 PM	#7
kw Registered User Join Date: Jul 2000 Location: Owings, MD Posts: 119	Got it... New fuel filter, distributor cap, wires and rotor button, and it's running just fine. Thanks, everybody for the help. Kurt

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06-10-2005, 01:41 PM	#2
aggiedave98 Senior Member Join Date: Aug 2003 Location: Sugar Land, TX Posts: 1,007	it's under the frame rail on the passenger's side about mid-way down the truck.

06-10-2005, 07:51 PM	#3
bisquik65 Account Suspended Join Date: Apr 2004 Location: N.C. high country Posts: 6,107	Take your dist cap off,and rotor ,look at the magnetic pickup on the shaft..(the part with 8 points on it) If its cracked ,then you need a distributer...Very common problem with the TBI engines...And if you get a reman one,look at it good . Make sure the module is new..i bought several of them and an old module on them..I change them all the time...I but its cracked in yours from what you are saying...The dist on these TBI motors controls the injector pulse,if its not right it misses... Erick

06-10-2005, 11:45 PM	#4
poolcues Registered User Join Date: Mar 2005 Location: Charlotte,NC Posts: 24	check the injectors.take off the air cleaner,crank the engine and see if the spray pattern coming from the injectors is a conical spray,if not they're easy to replace. other than that you can run some codes,post them and wait for an answer. good luck

06-14-2005, 04:18 PM	#5
toroflow Registered User Join Date: May 2005 Location: Anaheim, CA Posts: 103	Also it might be your throttle body to intake manifold gasket. Is the idle faster than normal at idle? If so, you have a bad TB gasket...this seems to be a common problem. Good luck.



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