Hi Everyone,
I’ve posted on here a few times about my difficulty in figuring out why my car would stall under load when cold-backing out of my garage and turning it around, etc. I diagnosed the purge evap system, the IAC valve, the TPS, vacuum leaks, spark plugs, cleaned and adjusted the throttle body, checked the coolant temp and intake air sensors and made sure no air was making it unmeasured into the intake. I also completely cleaned out the PCV passages. None of this solved the problem. It turns out that changing the transmission fluid solved the problem! I found this to be irritating as I took the car for a transmission fluid and filter change about 10k mile ago and the problem started shortly thereafter. This was at a mechanic whom I no longer use as I have discovered that they lie about their work. I checked the fluid the other day and it was brown, so off to a better transmission shop it went. Now the car is symptom free. I have a feeling the previous garage did not change the fluid at all. I’ve read that the XJ40 engine does not like problems with the transmission fluid levels, so I figured at this point, I should check. I didn’t even get that far, since seeing the color of the fluid, I knew it had to be changed. If I hadn’t done so, I would have wasted more money on a new set of plug wires and ignition coil. Oh, I also changed the cap and rotor about a year ago. I wonder if the other problem-occasionally stalling when accelerating from a complete stop was caused by the transmission also? It has done this exactly 3 times in the last 3 years.