That does sound like a worn poppet valve in an injector. The symptoms are right for it.

 

Now I am thinking that I have more than one problem, which really isn't surprising. I know there are a lot more than just two, but the others can wait while the critical ones get taken care of, I just have to figure out what the root issue is. One bad injector, even the elec. part of it, won't short out the rest for a brief moment, will they?

 

If there's a high to low side short in a solenoid or the wiring, the IDM can shut down a whole cylinder bank. That would normally be accompanied by a MIL and a P1316 code. It doesn't sound like that's what's happening to you, though.

 

I don't recall; did you pull off the 42 pin connector and inspect the underside for wear against the valve cover?

The one cylinder not working initially on a cold morning can be a bad glow plug too. You can ohm them from the valve cover harness connection on the head so checking them is easy.

 

how tight did you pull the zip ties? if they are pulled too tight they can damage the wires in the harness and cause intermittent problems!
do you have the adjustable pedals? they were known for wire chaffing. Some trucks with out adjustable pedals had similar chaffing problems with the throttle wiring where it went over the steering column.
a short to ground in the throttle wiring causes the potentiometer in the tps to burn the wipers, a new tps will be able to work for a while until the wipers get burnt and than the problems return.
also remove wiring from cps up to the main harness and check for damage. it sounds more cps than throttle to me and being that it is effected when you hit a bump it sounds like a chaffed or pinched wire.

 

I don't think I burned the wipers in the TPS, as all three, the two junk yard and the brand new, acted up almost instantly. Thinking of it now, I don't think I really looked at the harness for the CPS, I crossed it off the list when I swapped with my spare. I did the TPS originally because of a code, thought I just happened to get a bad one, so I tried another, then went for a brand new one. The CPS does make some sense, but its almost as if the engine goes to idle and comes back. It doesn't die in other words. I will go out and check for chafing and remove my zip ties and see what I can around there. I don't remember how tight I pulled them, but I'm sure it was snug. I mechanic on rental equipment, and we all know how well customers treat rental equipment, so I see a lot of weird things, such as carbon in broken wires showing continuity, until you put any actual current through it. I do not have adjustable pedals, but its not going to hurt to look anyway.

 

While I'm thinking about it, would the IVS override the TPS?? My pedal has the two separate units, maybe the contacts weren't dirty, but possibly broken? On a good note, my truck averages around 15mpg, Saturday I filled up and got 17.6mpg. I used to average that, but haven't in a long time. I thought it was a fluke. Since Saturday I have put 135 miles on it, topped off today when I got back to town, and got 19.2mpg! Maybe I don't have to fix anything...

 

this should rule out the cps as it needs the reading all the time,
when you are in cruise the throttle potentiometer and idle validation switch are out of the system.
I would be seriously looking for a wire issue. get a schematic and check all the wires to the throttle assy., hook it up to each wire in the circuit and have some one shake all the wiring while watching the meter. an analog meeter works best for that.

 

sorry, I missed your post and repeated the info you gave.

 

I did give everything a wiggle and poke, even had the throttle held slightly while doing it but to no avail. Maybe the meter will work better. Gotta add a new tool to the arsenal of tools. I have three good DMM's but no analog.
These symptoms happen only while maintaining speed, very rarely when accelerating, never when coasting. I pulled apart the 42 pin connector, removed my protector and felt along all the wires, giving them a little bend to look for a break. They look like 14 year old wires should. The protector was able to slide when pulled, so I don't think the zip ties were overly tight. I put on a layer of splicing tape and a layer or two of scotch 88 instead of the zip ties. I looked at the entire harness under the hood and dash, looking for any signs of rubbing, and didn't find anything there either. I'll get back to you on what I find with the analog meter.

 

Just tried to pull codes for grins…got the usual key in circuit malfunction (its unhooked) but I also got P1211! So, ICP above/below desired... No MIL… New ICP…New IPR…New fuel pump…I'm lost.

 

I'll bet you're driving home from work and you're at about the same location at about five O-clock when this happens.

Some aftermarket ICPs freak out with RF interference - which can happen near cell towers or another transmitter.

 

The truck acted the same with the old ICP as well as the new one. As far as I know, the old one was the original with the truck. So not to completely rule RF interference out, its just not likely. I've been driving the same path for around 5 years, and this has only been going on for the last 4-5 months, the new ICP is only 2ish months old. However, if it is the same brand of aftermarket, is it brand specific that has problems, or just a few in the bunch?

 

Brand-specific. You can always note your location when it happens, to see if there is a pattern.

 

One of the things you're fighting here is the reporting or scanning time for your engine. It sounds like whatever the problem is, there is not enough time for the problem to be logged by the PCM, before the problem goes away. Intermittent electrical gremlins are like intermittent relationships-they are a pain. I am not calling your truck any names, but it can get mighty frustrating.
Grasping at straws here:
Follow Tugly's advice-Change out that ICP
Bad batteries, even those that check out load wise can generate electronic noise which can confuse auto electronics. (Internal high resistance connections in the lead)
Disconnect batteries, temporarily spice in an electrolytic capacitor (not a large one) into the 12 volt PCM 30 amp circuit.
Disconnect that fuel heater temporarily
Replace the PCM relay with new, not used (arcing contacts in used relays can cause problems)
Cut into the PCM power feed wire, refeed temporarily from battery thru it's own fuse
When you cleaned the PCM ground area, did you look at the ground wire terminal for signs of corrosion?
Install temporary ground wire from Drivers battery to that same ground wire terminal for the PCM. You can drill and tap and 8-32 screw into the lead, if you want.
Inspect those battery cable terminals carefully for corrosion-it can be hiding in the copper wires. If you see any-replace cable
Remove the ground cable on passenger back side of engine and inspect that now visible end for signs of corrosion. If the end has any signs of rust, the bolted connection on the back of the head may have a problem. Try to find a new bolt location-obviously do not use valve cover bolts. Since the heads are aluminum, use anti-seize lubricant designed for aluminum electrical connections-does not contain copper!!!! The aluminum threads in the head are part of the connection and will be corroded if a copper antiseize is used on the threads.
Look at your 42 pin connection both male and female with a magnifying glass for corrosion. Use a bright light-those are tiny pins.
Look at all sensor jumper connections like MAP, CPS, etc. for corrosion. Even look at the new ones especially the engine side-did you inspect when CPS and ICP were replaced?
This is a tough one, but the fuse blocks and power supply connections to them from the back side can develop high resistance connections, especially the one under the hood. The block under the dash and under the hood, can actually have problems if a fuse was overheated by heavy load before blowing (like the fuel bowl heater). The heat stresses the factory crimped on wire connections, resulting in loss of tension in the connection. This then causes more heat in the connection and corrosion.
Good luck gengine, Larry