EGR Blues
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Freshman User
Joined: Jul 2002
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From: Rio Rancho New Mexico USA
The truck will run better with the vacuum line to the EGR disconnected regardless of whether the line is plugged or not. I have to admit that I have always had an intermittent miss at idle for as long as I can remember. Fortunately the truck does not need to be used much, so I have time to troubleshoot.
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Freshman User
Joined: Jul 2002
Posts: 28
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From: Rio Rancho New Mexico USA
Maybe Not The EGR Blues
I replaced the spark plugs, distributor cap, and rotor since they were well worn and the truck appears to be running a little better now with these new ignition parts, but the bucking and hesitating is still there. All six of the old spark plugs had a strange "Reddish" deposit on them and I suspect it was from the fuel additives that I had been using. I then removed the throttle body and the air by-pass valve and cleaned them thoroughly and reinstalled with new gaskets. There was a slight improvement in driveability, but the bucking and hesitating is still there. I also replaced the PCV valve with no improvement. There is still an intermittent miss at idle whether it is warmed up or not. The strange thing is that there are times that it will drive very smooth at certain throttle positions even with the EGR valve connected and no restrictor plates or washers. I will start looking at all hoses and the various cannisters, control valves, and the air pump.
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Freshman User
Joined: Jul 2002
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From: Rio Rancho New Mexico USA
EGR Blues <Problem Fixed>
I completed inspecting the remainder of the vacuum system and I did find the Cannister Purge Valve stuck open causing a constant vacuum leak, so I cleaned it out with carb cleaner and that cleared the stuck valve and I thought for sure that would fix the bucking and hesitating problem, but it did not. So then I decided to go back to checking the ignition system out again and decided to check out the spark plug wires and I found out that 5 plug wires had a resistance of 6000 to 8000 ohms and one had infinite resistance (Broken wire). Since the plug wires were covered under warranty at NAPA, I got a new set for free. I checked the resistance of the new wires befoe install and they were in the 2000 to 3000 range, much lower than the old ones that had only 10,000 miles on them. After the spark plug wire replacement and no other changes or fixes, the truck runs great!, like when it was brand new! I know that some of the fixes and replaced parts in the past two months is helping to make it run so smooth and this is without any EGR restrictor plates or washers. My truck has not run this good since the early 90s. I am a happy camper 
Elder User
Joined: Dec 2003
Posts: 660
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From: Northern California
Originally Posted by martinez_90
I completed inspecting the remainder of the vacuum system and I did find the Cannister Purge Valve stuck open causing a constant vacuum leak, so I cleaned it out with carb cleaner and that cleared the stuck valve and I thought for sure that would fix the bucking and hesitating problem, but it did not. So then I decided to go back to checking the ignition system out again and decided to check out the spark plug wires and I found out that 5 plug wires had a resistance of 6000 to 8000 ohms and one had infinite resistance (Broken wire). Since the plug wires were covered under warranty at NAPA, I got a new set for free. I checked the resistance of the new wires befoe install and they were in the 2000 to 3000 range, much lower than the old ones that had only 10,000 miles on them. After the spark plug wire replacement and no other changes or fixes, the truck runs great!, like when it was brand new! I know that some of the fixes and replaced parts in the past two months is helping to make it run so smooth and this is without any EGR restrictor plates or washers. My truck has not run this good since the early 90s. I am a happy camper
Waay cool there M90.......
Glad you're up and running as "new" again.
Myself.........
I'm running MSD Superconductors with near zero resistance and I've still got the stumble.
I'm sure I've got a vacuum leak somewhere....probably in the lower intake area.
Thanks for posting your cure for the dreaded "stumble" !!!!!
Happy driving,
Bob
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Joined: Mar 2002
Posts: 3,545
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From: Coal Region
i tried all of these same things and still have a intermitant miss at idle/part throttle.
i went as far as soaking the IAC in b-12 chemtool overnight and nothing changed. i suspect it may be the plug wires, since i havent touched them. with the persistant rain we've been having it looks like i wont be able to for a while either.
i went as far as soaking the IAC in b-12 chemtool overnight and nothing changed. i suspect it may be the plug wires, since i havent touched them. with the persistant rain we've been having it looks like i wont be able to for a while either.
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Freshman User
Joined: Jul 2002
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From: Rio Rancho New Mexico USA
This makes the fourth set of spark plug wires in 88,000 miles, so I will be checking them at every spark plug change from now on. There were a couple of other things that I did try to correct the problem, PCV Valve change and bottle of "Techron" in the gas tank, but those did not help solve the problem like the way the spark plug wire change did, but are probably a contributing factor in helping it run so smooth and strong now. I have been going a week now and still no problems with bucking, hesitating, or the intermittent miss at idle.
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Joined: Dec 2004
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I put a restrictor plate in with an 1/8 hole and my stumble is gone. I can still feel a 'flat spot' in the throttle under mild acceleration at the old stumble speed, but nothing like it used to be.
Now I can drive without spilling my coffee!
Now I can drive without spilling my coffee!
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