Vehicle Speed Sensor Problems
Hey all! I've got a recurring problem with my truck, and I was hoping someone could shed some light for me.
I have a 97 2500, 4x4 with a NV4500 tranny, a NP242 transfer case, and the stock 360 under the hood.
Back in February, coming back from Cadillac, at around 60 MPH she started bucking and ******* out.... did that 2 or 3 times before it finally corrected itself, displaying a "Check Engine" light. Made it home, no problems. Eventually the Check Engine light went away, so I didn't think nothing about it.
About a month or two ago, the problems began to surface. She started ******* BAD BAD BAD. I couldn't even get it upto 15 MPH without having it in 4th gear (yes, 4th gear). It took me over 30 minutes to get home, a half mile away. Got home, parked it, and began to work on it.
I went down and got an ODB2 code reader from Auto Zone, which diagnosed the problem as a "Vehicle Speed Sensor Failure". Great! Wonderful! That's so much easier than I thought it was going to be. Went down to AutoZone and got a new sensor ($50) and popped her in. And everything was fine and drove great....
....until the next day. Next day, same problems. Since this was nearing the end of my semster, in the parking lot she sat until today.
Today, I began to tackle the problem again. Pulled the vent hose and breather, all checked out fine, no cloggage or obstruction (I began to think there was an obstruction that was causing ATF to come out through the VSS, perhaps). Took her for a drive with the 4 vacuum hoses on the transfer case disconnected, still the same trouble. I'm nearing the end of my troubleshooting capabilities, and have no idea what is causing this problem.
She starts and idles ok, then as soon as I give it some gas, RPM's drop drastically, almost to the point of stalling. The more gas I give her, the more the RPMs drop. And what's worse, is the sound. It sounds like I tried swapping out my 360 for a Geo Metro 3 cylinder. A very very high pitched whinny sort of sound.
Some miscellaneous info for ya: when I replaced the VSS< I checked the voltages. The signal voltage was in line with what my Haynes reported it should be, however, my ECM voltage was 5v when it was reported in the Haynes that it should be 8v.
Is it possible that I just got a crap sensor? Or could there be an underying problem with the ECM? Maybe the ECM is damaging the sensors, or perhaps my ECM is just malfunctioning altogether?
Has anybody else had any similar problems? I really really love my truck, but if the ECM is failing, I think it may be time to trade her in for one of the new Power Wagons....
Whatcha all think?