mustangracer

I have a '97 with an automatic that is acting up. The tach will periodically drop while I am driving, along with the voltmeter, a/c, and cruise. When it is really bad the tranny dies as well (3rd gear only w/ no lock up). It seems to be at its worse when the truck is under load (up hill). I have been searching like mad on this forum and have learned that it's probably related to the CPS (crank position sensor)/ESS (engine speed sensor). The frequency of the problem seems to change if I move around the wiring harness (specifically at the front of the head behind the upper rad hose). This makes me think that perhaps its a wiring issue and not nessessarily the sensor itself. I want to check all the grounds and what not before I replace the sensor. My questions are as follows...

1. I know that others have had this problem as well. What worked for YOU to fix the problem?

2. Are there any grounds that I should pay particular attention to?

3. Am I possibly barking up the wrong tree? Might it be another problem all together? (I had tried unplugging the TPS but it still acts up when the TPS is unplugged. Might it be a different sensor?)

4. What are the following? IAT VSS (vehicle speed sensor???) WIF (water in fuel???)

Any help is greatly appreciated.

Chris

jmkennemur

iat is idle air temp. mine was doing the same kind of things. turned out to be the vss. mounted in the top of the rear differential. need to service diff if you haven't already and make sure there is no glitter in it indicating bearing failure and check the carrier bearings in diff for movement up and down. i have seen one with same problems that had bad bearings in diff causing too much clearance between vss and tone ring.

infidel

First of all 12 valves don't have an CPS.
Sounds like the problem is the ESS or the wiring/connectors to it.
IAT= intake air temp