The upshift delay valve is emissions related only. It wont be hurting anything with the engine or transmission. It keeps the engine at higher rpm's before shifting to a higher gear so the cat heats up faster. Shuts off around 40 degrees C. The electric vacuum switching valve that gives the upshift delay valve the vacuum is located by the brake booster, the green line goes to the valve, and the black line supplies the vacuum. You can test the valve itself by using a vacuum gauge and suppling vacuum to the green line that goes to the valve that is part of the detent cable, if it holds it, it is good. Sometimes though it is a vacuum supply issue. Make sure you have vacuum going to the switching valve first. Like I said before, it is not hurting the car at all. It is just for smog only. If you need to replace the valve it is cheap and not a bad job. The valve retails for about $38.00, and you need not drain any fluid on the transmission, but you will have to adjust the cable.