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hey guys having searched on the forums and countless other websites and not finding an answer to my problem i bit the bullet and opened a new thread.  i thought that ive been imagining this but it became clear last night i have not.  i was driving home and all the sudden the truck fell on its face and immediately regained itself. leaving me all but kissing the steering wheel and putting me back in the seat again.  ive replaced the tps and set it to the right voltage using cruisers tips, the iac, o2 sensor. also at idle sometimes the truck wants to idle down to 200 rpms before coming back to a loopy inconsistent idle.  its got me worried that I'm not gonna be able to make it home one of these days. 

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Not what I wanted to hear even though it's been coming to my mind too. I should add that I also have a random high idle, like a 2000 rpm high idle and it lasts for as long as it wants until it goes to the rough idle. Also it's been taking longer to start lately.

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I had a bucking issue for several years, a quick loss of power followed by a feeling that the clutch had just been slammed into engagement (For those who haven't experienced this... be stopped in your truck, rev the engine, then let the clutch slam into engagement, then you will have an idea what this bucking feeling is).  Dealer troubleshot it as CPS. I replaced it and nothing changed. Dealer wanted to charge me for another two hours of labor to "get" to the ECU. They refused to "gratis" any labor to compensate me for the faulty diagnosis. I swore them off. Eight years later I resolved to fix this issue, which lead me to this site.


I did a number of Cruisers tips, especially 1-5.


I discovered the diaphragm spring in the EGR transducer had rusted to powder. Additionally, the bleed air port and the port for the exhaust pressure to activate the transducer were basically clogged (I always suspected the EGR over the years).


While I was waiting for the EGR valve to come it (have to order the whole valve to get the transducer), I decided to order new plugs, new wires and a new coil, since there was a good deal going on and my coil was the original (this was in 2015).


Unfortunately, I broke a plug wire before the EGR came in. So I had to wait for everything to come in and replaced them all at once. Truck ran correctly for the first time in 8-9 years.


Hypothesis - Perhaps the combination of a weak spark and an EGR that was pretty much open was the cause. I still have the old parts and could rotate them in to try to isolate which one it was or if it was both, but I don't really want to subject my truck to that bucking ever again.


Hope my experience helps.

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Hopefully your coffee (or other drink) has a lid. I've worn mine due to it.


I never sensed my RPM's dropping during the "event". Just "hesitation", then "slam".


If I had to start over again, a new coil would be first. Reason is, if it is the original it is high time to replace it. You can get them for $30-$40 easily (or better). Might be able to replace coil, plugs, wires, cap and rotor for around $50-$60. To others.... I know that is lower end stuff and I am a blasphemer.


An EGR will run about the same amount as all that......and if that is the original, the transducer likely looks like mine did.


I wonder if incomplete detonation (unburned fuel), sucked back through a constantly open EGR, the hot exhaust gas causing early detonation of new fuel being compressed (and a planet going around the sun is like an electron around a nucleus....). I probably shouldn't drink beer thinking about this.

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  • 2 weeks later...

ok ive replaced the egr and it seems to have stopped! yay.


on another note i had to pull the head to replace the freeze plug on the back side of it. now when every now and then when i give it throttle it has a hell of a bad misfire symptom and goes to a 200 rpm idle like zone. it i let off it almost dies, catches itself and runs fine. or if i mash the throttle down it picks up but still had the misfire threw the rpm range.  now once i let it idle after the event in question it runs fine for a short while and then starts acting up again.  mainly it occurs when i try to pull out being i don't like using gobs of throttle when i let the clutch come up. any help is greatly appreciated 

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I assume your original problem has not replicated itself since you replaced the EGR (driving along and then give you a buck)?


A new coil solved most of this current problem, which appeared after pulling the head, or is it tied to the original problem?


Hopefully you have done Cruisers tips. If not, I highly recommend to go back and start there before you invest any more money. Cleaning the C101 connector sucks (as does the fuse box connector). Cleaning (refreshing) the grounds is easy. Even though you replaced the TPS and adjusted it, check the adjustment again.

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Its a new problem that occurred after pulling the head. A new coil fixed most of the current problem l. The old one was rigged to fit an msd two wire coil. But I've done some of the tips. The sensor grounds, ground cleaning, adding a ground wire, and yes I've checked the tps. Tryed a new one and check that twice. Also checked my vacuum lines and all wire connections. Did a fuel pressure test and it goes to 39 with the key one but doesn't hold the pressure. It drops down to 0 in 2 seconds. But holds 32ish lbs at idle. That also drops to zero in seconds when the truck is shut off.

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