02 Galant GTZ - jerky shifts & rough idle

My 02 Galant idle and shifting is just terrible, in a word. Here's what I got:

- low idle (400-500rpm)
- high idle (1200 rpm. I punch throttle and it comes down to normal)
- jerky shifts both up and down
- poor gas mileage (22mpg on mild weather, hwy miles)

So I did a extreme amount of searching and I find that all signs point to TPS adjustment. Anyone agree?

Now, I go to TPS adjustment in the manual and they are calling out for a special tool MB991348 and from what I'm gathering here this is just a manufactured splice between the TPS and the connector to do various checks from voltage to oscilating checks. I understand all of that, but I dont have this special tool. I look to buy it and online sites want $100 for something I'm going to probably use once in my life. Autozone, Oreilly, advance only carry generic tools. Anyone have a remedy for this? Can TPS checks be done without this special tool? Any suggestions would be appreciated. I hate the thought of exposing a couple wires to get my multi meter to.

Would also like to hear some opinions on my symptoms for any other things I need to check. Transmission worked just fine before I tore into it and re sealed the leaky valve covers on both banks. ignition timing is perfect, new rotor and cap, new spark plugs. wires did not replace since their resistance checked out perfect. did a basic tune up in other words and landed with all this crap going on.

Thanks for your time.

Kevin

My only suggestion is to check your motor mounts. Obviously it could be something else, but my mounts are bad and cause shifting problems.
One easy check is to have someone hold the brake and depress the accelerator, if the motor looks like its going to jump out then it's the mounts.
Another thing I observe is try to keep a steady 40mph on a level driving surface, if you feel a bouncing vibration it's the mounts.

It sounds like youre car is in its "Learning" mode. If you unplugged your battery everything got reset, idle and shiftpoints. You will just have to drive it for these things to go away. Usually takes about 15 minutes of driving. Give it a day and see where you are. Also should have cleaned the throttle body.

it's not the motor mounts. I've wrapped that motor up to 5k by hand and doesnt move around a whole lot. plus this is since I've done a tune up and that's been over a year ago now, if not 2 years ago. So it's not in learning mode either. Just recently I've noticed it getting worse. I have also replaced both o2 sensors and fuel economy is the same. 22mpg. Just ridiculous. I need to check that TPS but I dont know how to without the manufactured splice.

Anyone rig something up or have a remedy for that? cleaning and resealing the TB is a good suggestion. I might try that. In my experience with automotives a dirty TB being the culprit on a day-to-day driven car is quite rare. more notable for cars that are rarely driven or carb systems. but I will eliminate that.

But again, someone out there know how to check the TPS without ponying up $100 for the tool? Do I need to have the connector plugged to the TPS to check voltage? Obviously a code will be thrown but I'm just checking voltage, not oscillations that require the car to be on. Any thoughts?

Thanks.

another symptom is the idle will be 1200rpms. I punch the accelerator and idle drops to 500 bogging like crazy. when in gear the rpms go down to the desired 800-900. I've tried adjusting the throttle by hand but just seems to hang up at different idle speeds.