1994 Camaro Z28 auto trans - high idle, rough shifting at 3,100rpm

Hello,

My 1994 Camaro z28 auto has a high idle between 1,200 (when engine has warmed up) and 2,200 rpm (when cold).
It also shifts (jerks/lurches) hard when going from park to reverse and very hard when going from park to drive.

When the engine is cold and on the road, the car won't shift up out of 1st gear at all. When it warms up, the car will up shift but only when the tach hits 3,100 rpm.

I'm hoping someone will be able to help me get to the bottom of this because it's my only vehicle and i just started a new job and can't be without wheels..

The SES light is on and now it stays on. At first, it used to come on only when the car was cold and it would go out if i turned the car off and re-started the car after it had warmed up. Then, once it warmed up, it used to shift fine and the trans was smooth shifting. The trans hasn't ever slipped or acted up before and the trans fluid looks like new.. it isn't burnt or burnt smelling.
I took the car to Advance auto and they told me that the plug in test unit they had would only work with cars back to 1996 or 1997 and that i would have to take the car to a gm dealer to get the code and that it would cost quite a bit of $ to have it done.. just to get the trouble code! :headshake

I was told by a friend that it most likely was the TPS (which i changed out today - problems remain) or could be one or many vacuum leaks (i have no idea where to look for vacuum lines under the hood, but do know that i can spray carb cleaner around to try to pin point them - locations/photos of the vacuum lines would be awesome) or mass air flow being dirty (i've located that and will take that out and check/clean it tomorrow morning) or transmission solenoid 1-2 3-4 (have no clue where they are but thought they would be inside the trans) or a sticking throttle body or linkages (which i sprayed even though it all already appeared to be free moving) or EGR (i'm not sure where that is located, but found something that could be it on top of the engine on the drives side).

The car recently had the optispark module changed (for the 4th time in 15 years - what a crap water holding design work of art huh lol) and the plugs and wires are new. The car ran and shifted fine after that work was done and that was months ago..

I did read something about having to rotate or adjust the TPS after installing it to get a voltage of .64 or .65v or something.. and i do have a meter, but more detailed instructions would be helpful so i don't damage anything.
I thought that they TPS could just be mounted in place and had no idea that it needed to be rotated slightly to get it in the proper location. I thought that the onboard computer would sense where it is at rest when throttle is closed and the vehicle is at rest and then make adjustments from there?

I'm sorry this post is so long, but i'm at wits end with this guys. I promise not to make such long posts in the future heheh.

Any help would be great!

Steve :)

The SES light is on and now it stays on.

I was told by a friend that it most likely was the TPS (which i changed out today - problems remain) or could be one or many vacuum leaks (i have no idea where to look for vacuum lines under the hood, but do know that i can spray carb cleaner around to try to pin point them - locations/photos of the vacuum lines would be awesome) or mass air flow being dirty (i've located that and will take that out and check/clean it tomorrow morning) or transmission solenoid 1-2 3-4 (have no clue where they are but thought they would be inside the trans) or a sticking throttle body or linkages (which i sprayed even though it all already appeared to be free moving) or EGR (i'm not sure where that is located, but found something that could be it on top of the engine on the drives side).

Well, first thing you gotta do is read the codes (betting there is more than one).
Don't worry about setting the TPS, starting in about 1990 they were no longer adjustable. The computer takes care of doing the Null on it.
Vacuum lines...look at the back of the plenum and charcoal cannister and up at the throttlebody. There should be one or 2 going to the EGR and one to the fuel pressure regulator. There are actually very few vacuum lines on EFI cars (thankfully). Also check/replace the hose and check valve going to the power brake booster (big black thing on the firewall on driver side)
Transmission solenoid is in the trans and that is where getting the codes read comes in.
Also, when's the last time the transmission filter and fluid were changed?

Well, first thing you gotta do is read the codes (betting there is more than one).
Don't worry about setting the TPS, starting in about 1990 they were no longer adjustable. The computer takes care of doing the Null on it.
Vacuum lines...look at the back of the plenum and charcoal cannister and up at the throttlebody. There should be one or 2 going to the EGR and one to the fuel (http://www.automotiveforums.com/vbulletin/#) pressure regulator. There are actually very few vacuum lines on EFI cars (thankfully). Also check/replace the hose and check valve going to the power brake (http://www.automotiveforums.com/vbulletin/#) booster (big black thing on the firewall on driver side)
Transmission solenoid is in the trans and that is where getting the codes read comes in.
Also, when's the last time the transmission filter and fluid were changed? Thank you so much for the response.
I will check the things you mentioned.
The power brake booster is very rusted, but i will check the lines that attach to that.
I'm not sure exactly where the EGR is. I found something that looks kind of like a metal plug that has a spring loaded thing in it that rattles when i shake it. It has a hose attached to it that goes in a "U" shape, right back into the top of the motor. If that is the EGR, it didn't look to bad, but it is the original part so i know it's old. Is that an expensive part to swap out and is it worth doing? Could that be causing the high idle?
I'm glad i don't have to mess with the TPS, but i was kind of hoping that it may have been the reason for the high idle and the rough shifting, but so much for the hope of a quick fix. :(
The trans fluid hasn't been flushed/changed in years. The car has 150k original miles on it and i think the trans fluid was done back in 1999. The car never was garage kept and most of it's life was spent in pennsylvania and upstate new york where the winters were harsh.
So, it's looking like i have to find an economical way to get the codes, then get the trans filter and fluid changed.
Thanks again for the help.

Here is a link with some pics and explaination of your EGR http://shbox.com/1/4th_gen_EGR.html

The 1994's were OBD I but used an OBD II style connector. A simple code reader is all you need for now, like this one http://www.gadgetsgalorestore.com/google_details.php?id=134 To diagnose it further you'd need a scanner to do a real time read of what is happening. For now though just getting the codes will be a big help.

Try autozone, I think they can read pre-OBDII cars.

The diagnostic trouble codes can be read by grounding test terminal B. The terminal is most easily grounded by connecting it to terminal A (internal ECM ground). This is the terminal to the right of terminal B on the top row of the DLC connector.
Once the terminals have been connected, the ignition switch must be moved to the ON position with the engine not running.
The Service Engine Soon or Check Engine light should be flashing. If it isn't, turn the ignition OFF and remove the jumper wire. Turn the ignition ON and confirm that light is now on. If it is not, replace the bulb and try again. If the bulb still will not light, or if it does not flash with the test terminal grounded, the system should be diagnosed by an experienced driveability technician. If the light is OK, proceed as follows.
The code(s) stored in memory may be read through counting the flashes of the dashboard warning lamp. The dash warning lamp should begin to flash Code 12. The code will display as one flash, a pause and two flashes. Code 12 is not a fault code. It is used as a system acknowledgment or handshake code; its presence indicates that the ECM can communicate as requested. Code 12 is used to begin every diagnostic sequence. Some vehicles also use Code 12 after all diagnostic codes have been sent.
After Code 12 has been transmitted 3 times, the fault codes, if any, will each be transmitted 3 times. The codes are stored and transmitted in numeric order from lowest to highest.

These have the old style GM 12 pin connecter. You can pull codes without a scan tool. The egr valve is on the back of the intake manifold. It is probably bad if it has never been changed but most likely has nothing to do with the problem you are having. Try unplugging the mass airflow sensor and see if it runs any better.