Erratic Idle and CEL?

[stevechaos]

Ok, so thanks to using this place like a repair manual for the past couple of weeks I have been able to correct the dreaded timing chain guide death rattle.
I bought the 2001 2wd for a good price because it had the clatter, and I got the complete kit just in case. I tore it down and found only the main chain guide was shot. And by shot I mean completely gone. The frame was still there (somewhat) but the majority was broken and worn away. I don't see how the truck even drove with the massive amount of slack in the chain! Not only did it drive, it drove rather well. It was just loud.
Anyways, so I replaced the chain tensioner/guide on the main chain and found the one on the camshaft to be in good shape somehow (changed recently?) so I left it be and buttoned everything back down. I also pulled the oil pan and fished the broken pieces as well as the ground up metal pieces from the tensioner frame out, reinstalled and topped off all the fluids and such.
So then the moment of truth: I started the truck. It cranked right over and ran nice and quiet...for a few moments. Then the idle got slightly erratic for a bit and then smoothed out. It spit out some white smoke for a few seconds, but not for very long. I turned it off and cycled it on and off a few time and it always starts back up and runs ok, the only noticable issue being that the CEL is on and the erratic idle that seems to go away after a bit.
I'm not even sure where to begin looking. I figured it could be a vacuum leak, so that's my first course of attack, but then I have no idea. Could it have jumped time a bit since the chain was so sloppy? Seems unlikely, but nothing is impossible.
Any idea fellas? This is my first bout with one of these 4.0's, so I await your expertise.
Truck is a 2001 4.0 2wd.
Thanks in advance.

 

[2000StreetRod]

Read the DTC

I suggest reading the diagnostic trouble code (DTC) as your first step in the troubleshooting process.

Did you loosen the jackshaft front sprocket retaining bolt when you replaced the primary (crankshaft to jackshaft) chain tensioner and guide or just slide the old ones out and the new ones in? I assume that you "pulled the pin" on the tensioner.

Did you check the compression? It is unlikely that the primary chain would slip even without the primary tensioner. There isn't that much slop in the chain. If the primary chain slips then there would be low compression on both banks.

This thread identifies vacuum connections on my 2000 SOHC V6: Intake manifold vacuum lines Yours should be similar.

 

[stevechaos]

I had the codes pulled last night. They are 113 which pertains to the IAT, 301,302,303 which are all misfires in bank one and 172 and 174. Those two confuse me. They're both for bank 1, and one is for a rich condition while the other is for a lean condition.
Part of those are my fault. I started the truck without the MAF connected and haven't disconnected the battery since. Tonight I plan to remove the battery and let them reset and then have them run again.
I didn't take off anything except the tensioner itself because I didn't have the tool to keep the timing in line. Plus the right front cassette looked to be in tip top shape.
I haven't checked the compression, but wouldn't there be a code registered if I had low compression?
It runs fine. I've taken it up to 85 on the highway and it runs great. The only time it seems to struggle is at idle. In that situation it's got a heavy vibration. The really odd thing about it is that it it's only after you've been driving it that it seems to struggle with idle. When you first start it the truck idles fine as long as you don't give it any throttle. If you do as soon as you let off it then it immediately begins to hunt. The RPM's will jump and then level out around 1k and then the vibration starts.

 

[2000StreetRod]

clear DTCs and reread

P0113 Intake Air Temperature Circuit High Input
P0172 System too Rich (Bank 1)
P0174 System too Lean (Bank 2)

The IAT sensor and the MAF sensor are integrated on my 2000 and probably on your 2001. When the MAF sensor is disconnected the IAT sensor is also disconnected. Your P0113 may be due to the disconnection. I'm surprised there was no MAF sensor related code: P0100 thru P0104.

There is no sensor that allows the PCM to detect low compression. I think the PCM computes the power pulse of each cylinder when it fires using the crankshaft position sensor. If the power pulse is repeatedly weak compared to other cylinders then the PCM sets the misfire code for that cylinder. Misfires can be due to ignition, air/fuel ratio, or compression: Engine misfire procedure

P0172 is rich on the passenger side while P0174 is lean on the driver side. Your misfire codes are all for the passenger side. Did you disconnect the precat O2 sensors from the engine wiring harness? If so, did you reconnect them to the same connector or swap them by accident?

I suggest that you clear the codes, drive until the check engine illuminates and then read the codes again.

 

[stevechaos]

P0113 Intake Air Temperature Circuit High Input
P0172 System too Rich (Bank 1)
P0174 System too Lean (Bank 2)

The IAT sensor and the MAF sensor are integrated on my 2000 and probably on your 2001. When the MAF sensor is disconnected the IAT sensor is also disconnected. Your P0113 may be due to the disconnection. I'm surprised there was no MAF sensor related code: P0100 thru P0104.

There is no sensor that allows the PCM to detect low compression. I think the PCM computes the power pulse of each cylinder when it fires using the crankshaft position sensor. If the power pulse is repeatedly weak compared to other cylinders then the PCM sets the misfire code for that cylinder. Misfires can be due to ignition, air/fuel ratio, or compression: Engine misfire procedure

P0172 is rich on the passenger side while P0174 is lean on the driver side. Your misfire codes are all for the passenger side. Did you disconnect the precat O2 sensors from the engine wiring harness? If so, did you reconnect them to the same connector or swap them by accident?

I suggest that you clear the codes, drive until the check engine illuminates and then read the codes again.

Resetting the codes and then waiting for the light to pop back on was my plan, I just haven't gotten around to it yet today. I'm sure that it will clear one or two of them at least.

I drove it again today, and the results were the same as yesterday, it drives fine, but as soon as you're forced to idle then the vibration starts, and as soon as you take off it vanishes again. The only other thing I notice is that it doesn't seem to "take off". I have nothing to compare it's acceleration to as I didn't drive it but once before I did the work, and it drove exactly the same, just much noisier. my daily driver is a Mustang, so of course it's not going to have the same amount of acceleration as that, but it still seems a bit slow. I can get it up to 80+, but it accelerates slow and steadily. Maybe it is missing as I can see that affecting the acceleration.

I didn't touch any sensors except the MAF. I suppose I could check them to see if someone else might have before I bought the vehicle. Are there any other sensors I might need to check while I'm at it?