My 1994 3.8 Cougar pops lightly sometimes when cranking to start and occasionally the service engine light comes on. It also feels like the shifting is a little rough, especially down shifting. It did this before and after the installation of new O2 sensors and MAF sensor, plugs, mpls , wires. It has 63,000 miles on it. The codes cant be pulled because the code scanner can't connect with the car when scan is done (3 different shops).
I would like to replace the Throttle position sensor as I feel this might be the culprit. When replacing the TPS, do I just unscrew the old when and pop the new one in or is it adjustable and has to be set with a volt meter? In the tech article on tPS adjustment it says " Set TPS to 0.98 volts, set initial timing to 14 degrees." I have a stock coil pack, not the distributor and no access to a volt meter, so i dont think I can set the timing or TPS. Can I replace the TPS simply by installing the new one? Is the TPS non adjustable or adjustable by rotating on the coil packed 94 cougar 3.8?
Just take the new one outta the box and bolt it up.
There's no adjusting needed. Just bolt it up and go. The ECM will "learn" what the new sensor's closed voltage reads because when you start the car, the ECM will use the voltage it gets as a reference.
If your car doesn't have a distributor, you need not worry about adjusting any timing. You can't anyway without programming the computer.
I replaced the TPS today. I took out the throttle plate housing and hit the screws with an impact screw driver. Car runs real nice now. Shifts better but more importantly, no slight hesitation on acceleration. In the past i would step on the gas but would see very little or delayed acceleration. Accelerates as soon as i tap the gas and doesn't jump into overdrive on acceleration. Didnt show the typical signs of a bad TPS - tach was rock steady. New TPS was $33 at autozone. Thanks for all the feedback!!!!
Great, thanks, so, I can just take off the old TPS and put on the new one, cool, I could use this info. I'll try it and see what happens. Mine slips a lot too, and is hesitant to shift, or shifts to overdrive while driving like, 30 or 40 miles per hour. Thanks~!
Hope it works for you. Also , you might want to follow the tech articles and posts here and pump the tranny fluid out the cooler line, drain the TC and replace the filter and replace old fluid with Mercon V and one bottle of this http://www.lubegard.com/automotive/trans_atf.html . I got clear hose at home depot and a small brass nipple with the same threads as the tranny cooler line flare nut to help pump the fluid out. You can also attach the fluid drain hose to a scavenged piece of scrap tranny line and flare nut.
You dont have to change the tranny fluid ,it has nothing to do with the tps. However, if you are having shifting problems and currently using the older Mercon III you will notice in improvement in your shifting etc. I just did both at about the same time and cannot believe the difference in performance, it is like a different car. TC=torque converter, it has its own drain plug.