Ok, well i'm going to start when i bought this back in feb. so everyone one knows what i've done and went through and might help them give me a better answer....
1991 Trans Am
305 TPI
700 r4 tranny

I bought this car in Feb. of this year. When i test drove it i noticed the check engine light was coming on and thought no big deal, i can check codes and fix the problem. Well drove it home ( 105 miles back ) and didn't seem to have any problems or so i thought. Until i got a chiltons book and began reading because i have never owned/worked on a tpi. ( also the guy had told right before i left that he had put a new tps on it and i noticed it seemed to have a new alt too. ) After reading i noticed that the car was always running in ( safe mode ) and that is why i was pushing like 2 and half grand at 70 mph in OD. Well after a couple of days of messing with the tps ( had no idea what i was doing ) i finally broke down and did a lot of searching through google. Some sites told me .54 and others told me .71 and then there was one sight that explained everything and told me .54 for maf cars and .71 for SD cars. Well i could not adjust my tps that low and called the chevy dealer and ran the serial code # on it and found out it was off some other car. Well a day later and a couple bucks i had the right one ( i think not for sure ) The one i have now is none adjustable. After finally doing some reading on here a couple of months ago i realized that .54 was the best place to ahve it and now i get awsome responce!! Well to get it to .54 though i had to take my drimmel and make the tps adjustable cause if i just straight bolted it up it was at like .88 or something and that is something that just makes me go hrmmm still... Well i was still haveing an idling problem ( to where it would die on me ). So i did a little more research and found out how to reset and clean the iac and did so.
Ok now that i that part cover, i also want to mention in the first couple of months i was gettin a code for the egr and tps. I changed them both and got them both from the chevy dealer. Still throwing codes ( but after i got the tps lined out it does not. ) I did a couple tune up on it from front to back and after i was done it made the car idle even worse for a couple of days and then straightened back out and seemed to better. Well about a month ago i got tired of trying to figure out what was wrong with my car and took it to the chevy shop ( first time in my entire life ) and told them that it was not flashing any codes but something did not seem right. Well 4 hours later they guy told me he thought it was a coil in one of the injectors going back ( cause it sat for a year before i bought it ) and it was jumping from open to close loop. But he adjusted the idle up for me on it and i have no cluse what else. But it idled 10 times better now. There was still a small miss but figured it was that injector and i could live with that at the moment. Took it home that evening ( and remind you this is like 4 or 5 months later after my last tune up ) i decided since i had the extra cash i would do it again cause my car was running really good now. I did plugs ( no wires cause they were really good and dist. and rotor still looked new so i left alone ) put new ox. sensor on it and oil change and trany filter change. Well this time i gapped the plugs ( which i did not before. ) Also had to put new starter on it so the computer got reset also during this process. Well i started it up and once it warmed up it was idling rough again. Figured it would do the same as before. But now its been 3 weeks and has not cleared up. Just last week my coil went bad on me ( wouldn't work when it was extremely hot outside ) and i bought a msd coil for it and put it on. That stopped the out of the blue not even wanting to run problem that i had for like 2 days. ( btw it would out of the clear blue loose all power, and when i gave it gas it would wanna die out but as long as my foot was off the accel. it would idle for a min and die. I thought it was a fuel problem until the 2nd day it done it and i smelt it overloading itself and realized it was fire problem. )

Now to explain the problems i can figure out!!! I have no idea if any of these problems are realated to one thing or could be many different things.
1st. Going down the interestate at 70 mph it quick huge miss. Almost seems like it looses all full or fire for a split second and then its fine. ( Never has done it to me going 55 or anything, just down the interestate.

2nd. I think this is related to the problem about but not forsure. when climbing my driveway i have to go walking speed to keep from dragging and bearly pressing the gas. You can feel it missin all the way up ( never did that before the tune up ) Crusing at low rpms you can feel it also, not just under a load but on flat ground bearly pressing the gas.

3rd. I find this one the strangest. This only happends on close loop. But lets say my car is already warm and i jump in it and take off ( now if i let it sit for like 10 or 15 seconds and let the rpms come all the way down to 600 it won't do it ) but i can drive as far as i want ( distance is not an issue here ) and when i come to a complete stop it will idle at like 800 or so and ( not be missing ) and then after about 2-3 seconds it will drop to 600 and then start to miss. So what is up with that?

Also a question for you guys. I run ac delco plugs for now and when i bought the car it had shorts one in it. it was the # with a S at the end. Well the first tune up i did the guy sold me long ones ( with out the S ) and that really improved my idle. Well the last tune up i had they sold me the shorts and i went up there and exchanged them for the longs ( cause i figured since i had longs in there that is what i should put back in there )

I guess i'm asking which one's do u guys run?

Anything unclear feel free to pm or w/e and i'll try and explain better
Thanks in advance for any advice or suggestions u leave me!!!

 

Not in any particular order:

Unless you are using headers or angle-plug heads and need the extra room that shorter plugs can afford, use the standard length insulator, extended tip J-nosed, copper cored resistor spark plugs. Those would include Delco R43TS or Champion RV15YC4. All the plugs must be gapped at 0.035-0.040" with a stock ignition system.

If you installed an MSD performance ignition coil and did not install a higher current HEI switching module, there may be problems as a result. The stock HEI module cannot reliable handle the primary current that is demanded by the high performance coils, and may shut down as a result. Switching back to a stock coil may not solve it, since damage could already be done to the HEI module.

The best information I can locate indicates that the TPS voltage on a stock S/D system needs to be below 0.88V at startup. The ECM will interpret whatever voltage the TPS provides as the closed throttle position (so long as it is below the 0.88V threshold). You also want to check that the TPS woltage at WOT is at least 4.0V. You can also verify the TPS setting with a data scan of TPS percent.

If the dealership service department "set the idle up" they probably did you a disservice. Idle RPM is supposed to be controlled completely by the ECM via the IAC stepper motor. The only proper way to change idle RPM from the ECM target idle is to reprogram - Period. You can tweak the minimum air position to help prevent hesitation on throttle tip-in, but the eventual idle will still be controlled by the ECM. If the throttle is opened to the point where the idle RPM is above the target idle, the IAC will be effectively dead (counts will be nearly zero).

Stalling, misfire, lugging, and lack of power at cruise can be due to a sluggish EGR valve and/or deposits in the valve and EGR passages.

Misfire at low RPM load (climbing your driveway) could be due to several factors, including compression loss, weak ignition, poor injector spray patterns or imbalanced injector flow, and several other les likely causes.

 

I am having a similar problem but I am going after it differently. I am working with the gas now. The gas is very hot in my car and we can’t find out why, so I am replacing the fuel pump, sending unit and wrapping all the fuel lines. I will be able see if that fixes it tonight. I have worked at a Chevy dealer for 16 years and have many mechanics stumped on this problem. We have done drop test, node test, checked spark replace ecm, prom you name it. By the way if you took it to Fairground Chevrolet that was your problem! ( just kidding).I am from Missouri also. Bottom line it seem we have the same thing going on and it’s painful!

 

it worked, I couldn't tell you which one but either the pump or sender

 

i figured out what it was... my dist. was all messed up. flat plate had came loose that the dis. cap mounts to and i do have on injector that is not pulsing like the rest are. or not nearly as hard. But thank you all for your replys and help