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Old 07-28-2011, 10:21 PM   #1
SS Delux
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4.3L hesitating when "cold"

Ill get right into it, when i start my truck up for the first time after i let it cool down completly (overnight or 8 hour shift at work) it seems to hesitate on takeoff and during any acceleration. It is getting pretty bad and i want this fixed soon since it is my DD and my only vehicle. what could cause this ?
P.S. It is a 1987 with tbi and a 4 speed stick.
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Old 07-29-2011, 08:48 AM   #2
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Re: 4.3L hesitating when "cold"

anyone?
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Old 07-29-2011, 12:27 PM   #3
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Re: 4.3L hesitating when "cold"

Check base timing first. make sure it is at zero with the plug unplugged (under the booster)
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Old 07-29-2011, 10:04 PM   #4
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Re: 4.3L hesitating when "cold"

I timed it before I put it on the road a few weeks ago and I just checked the timing again, it is at zero when the plug is undone. Could it be an old cap, rotor, plugs and wires ? They are about 1.5 years old but the truck was sitting for a bit. How often do you replace them ?
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Old 07-30-2011, 02:20 AM   #5
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Re: 4.3L hesitating when "cold"

After the truck is warm does it run fine???? I have an '87 with a 350 that does the same thing when cold, but when it warms up its fine. I figure its a sensor that is not telling the motor its "cold".
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Old 08-01-2011, 11:44 PM   #6
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Re: 4.3L hesitating when "cold"

Yea, its runs great after it gets to running temp. What sensor could that be ? I already replaced the water temp sender in the manifold.
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Old 08-02-2011, 12:21 AM   #7
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Re: 4.3L hesitating when "cold"

Remove and clean the EGR and air idle valves. The O2 sensor could be failing. Have you tried to pully any codes?
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Old 08-02-2011, 09:51 AM   #8
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Re: 4.3L hesitating when "cold"

I have the same problem in mine, It Is really annoying, hope you get it worked out so I can to lol
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Old 08-02-2011, 06:16 PM   #9
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Re: 4.3L hesitating when "cold"

how do I clean the EGR ? and what are the air idle valves ? There is a new 02 sensor in it.
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Old 08-02-2011, 06:28 PM   #10
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Re: 4.3L hesitating when "cold"

Could be a weak fuel pump!Happened to me before!
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Old 08-02-2011, 10:06 PM   #11
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Re: 4.3L hesitating when "cold"

Remove the EGR valve. Using compressed air, blow out all the black carbon. Use a solvent cleaner and small brush for large carbon deposits. Check for operation. The air idle valve is on the throttle body. It is held by two small screws. Remove it and clean the rubber end. It may be distorted or ruptured. Check for operation. It will set itself after you start it up. There is a procedure to set it too. Check with www.autozone.com. The fix it your self area had factory directions, pictures and diagrams.
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