Engine/Transmission (1998.5 - 2002) Engine stumble

[NShadbolt]

I have had this very intermittent stumble since the end of last summer. It started out feeling like a small miss fire but over time it has gotten worse. It usually happens just after startup in second or third gear around 1800 RPM but it will sometimes happen even after running for hours. I can feel a slight miss when driving in second around 1800 once I get to 3rd it is like I let off the throttle very quickly and then stomped on it again. I have never got to look at any gages because my head is snapping around and it happens suddenly and quickly. On the really bad stumbles it throws codes 0122 (Throttle position sensor voltage low... . ) I am assuming they mean APPS. 0500 (no vehicle speed sensor signal..... ) But I am was told that manually trannies don't have the speed sensor and they use the ABS sensors. I origanally thought it might have been a problem with the Banks OttoMind but I unplugged it and have had no change. I have changed fuel filters, drained fuel/water separator, checked wiring and even talked to it without any change. Any input would be greatly appreciated.

 

[DHawthorne]

Had a similar problem when the Map Sensor went out on my truck. The crankshaft position sensor seems to make the guages and tach act funny. Don't know about the camshaft sensor.



Check the mileage indicator for a code number, if you have not done that already. Key, on/off twice, and on. It might be holding one or more codes.



Dave

 

[Makensmoke]

Because of design differences this may not even compare, but in a Chevrolet acting just like this, we are told its the injection pump. We are going to keep driving it untill it strands us, and its been going for quite some time. If your like me this isn't going to happen though, I can't stand my truck having something wrong with it. I see now you have a FP guage, so its unlikley that you've starved the VP and burnt it up, so I guess i'm talking myself out of my own guess as to what it could be... but I guess anythings possible.

 

[rkressg]

1. Get rid of the K&N (IMHO they suck)

2. Replace the MAP (Bet it is shot, thanks K&N)

3. Clean the APPS.

a. Unbolt the three 13mm bolts holding down the APPS, un-hook the wiring harness from the underside, clean connection well with electronics cleaner, pack with di-electric grease, and reassemble.

b. Clean the ECM wire harness in a similar fashion.

4. Disconnect the batteries over-night (at least 4 hours).

5. Reconnect the batteries, turn ignition to 'On' and with out starting, push the accelerator to the floor slowly.



This will recalibrate the APPS and usually fixes the problem. You can also disassemble the black box that encapsulates the APPS and clean the fingers on the sensor. Do not touch anything in there, just spray electronics cleaner on everything. Ensure that everything is dry before re-connecting the batteries.



Hope this helps.

-Rich