Now that it is starting to get cool again in the mornings lately I have yet again began to notice that without warming my truck up for atleast 10 minutes the truck will shake violently and lack tons of power. This problem existed while it was warm but is related to temperature in my opinion, because the less time it sits after being "warmed up" the less time it takes to "clear out". I have tried disconnecting the EBPV to see if this was the cause, to no avail. My other thought is possibly in the tranny? If I was to leave in the morning after sitting all night, and only let it idle for a few minutes it would be probably 10 miles down the road until something "releases" and then all is well, full power(atleast for a stock 2000 350 cc)smooth running, happy camper! As I said it is all relative to the amount of time sitting vs amount of time "warming up". For instance if I was to leave for lunch at work after sitting 4 hrs or so the truck would "release" by the end of the parking lot, but don't start it all day with the cooler weather we've been having now and not let it idle for a while its one rough running sob until it warms. I've been fine with letting it idle while i'm in the shower or something but i'd really like to figure out what is causing it and make it right.

 

Have you pulled any codes from the PCM?
Check the value of the exhaust back pressure sensor, be sure it's reading correctly. Check it with the engine off and with the engine running, the value should change.

That is where i would start.

 

Sounds like a loose UVCH connector to me.

 

Yeah, we need to get any stored codes pulled. Does the CEL come on during the rough running? It could be an IPR issue too. We've seen this happen when those start to go out. I think when they start to go, the thicker oil causes issues in the IPR. You might try putting in some syn 5W-40 to see if it clears that up some. If so, I'd start looking at the IPR. You can also pull the bolt off and see if there's oil in it. That's another sign of it getting ready to fail.

 

Thanks for the replies the CEL or the SES neither come on, I wasn't thinking about the harness, since it is consistently the same. No codes have been pulled either, need to find a shop around NW Arkansas that has an AE I guess or buy one. In earlier post I used the term "release" because there is no other way to describe it. Its as though you hit a switch. The theory of the EBPV was one of my first thoughts, I assumed unless it is mechanically bound up, that disconnecting it at the plug would eliminate this?

 

Ok performed the .50 Mod and inspected all harnesses under VC before I even started my truck today, it had benn sitting since about 2 AM last night. Started up let it idle about 3 minutes, started off down the road, turned onto the highway to begin accelerating, problem still exists, under acceleration, even mild, the truck shakes badly, let off shaking stops even try to baby it up shaking gets progressively worse the more you depress the pedal. About a mile down the highway all of the sudden like I said something happens like you threw a switch and smooth sailing? Again no CEL or SES lights? Starting to lean more towards tranny pressures though since as far as I can tell over the more pronounced rattling of the engine the tone out of the exhaust seems relatively smooth?

 

probably nothing in the tranny. mine has been doing this for awhile now and it's a stick. yes "release" is the perfect description.

 

Interesting, like I said I deal with it by letting it idle, but the main concern is when I have fishing tournaments my draw partner has to pull the truck to the ramp per rules, most accept the wait to start feature but not many will allow it to warm up fully before pulling around and then when they pull me out they're like I thought those trucks were supposed to be powerful, of course I wave when I'm passing them on the way home all nice and warmed up! LOL.

 

SOunds like to me is a sticking EBPV. I know when i was in Alaska and still had the EBPV, my truck would do the same thing, except the shaking. It was like it couldnt get out of its own way, but once it warmed up, holy hell did it take off. then i was told that is how the EBPV works. so i let it go until i installed a 38R and did away the EBPV. Now it doesnt happen anymore

 

It has to be something electrical cutting out for it to shake like that.
It is one or more injectors not firing.

 

Ken,

Like my first post I thought EBPV but with it disconnected electrically this should go away?

Dan,

I'm not doubting the electrical realm that is why I did the 50 cent mod today before even taking her out for a trip. The issue seems way to consistent to be loose connections or such, something more electrical like a sensor I would believe, but would think I would get a CEL. As I said earlier the amount of time warming up vs. time sitting off is almost calculable, meaning based on how long the truck was sitting I could tell you pretty close how long you would need to wait while warming up in order to take off without any issues at all. This is why I feel it is a sensor of somekind just not sure what to check into?

 

If some of the cylinders arent firing, could he look for a puff white smoke when it starts firing?

 

I've never seen the truck smoke barely a puff of black under heavy acceleration. Hoping to change that soon with my DP tuner

 

Definitely process of elimination item to figure out what the heck is going on.
Have you checked for blow by? Maybe the rings are loose?
Pop the oil cap and see if it is puffing real bad while it's warming up.

Check.....
for blow by (When warming up)
PCM codes
EBPV
IPR

What else can we check? I think codes need to be pulled asap, I'm sure that will tell us much of what we need to know.

When pulling codes what other values should be check with engine off and engine running?
I think the exaust back pressure sensor should be checked. You should be able to see the values of the EBPS after you pull the codes. I know mine needs to be replaced but it acts nothing like yours, then again my EBPS is stuck at 22lbs.

 

Thanks unfortunaltely I do not have a scanner, but will look into the dealership. What's the best way to check for blow by? Only a slight amount of oil is present in the intake? The truck rarely is even 1/2 quart low at oil changes. Would rings have to be checked with expensive compression tests, I was quoted once at $350 to perform compression tests about a year ago when this begin to occur?