I have about an hour to kill before I kill my car! I recently replaced my MAS as ECM/SES light was offering me a code 34 and one could smell the excess gas. I have replaced TWO of the MAS. I TRIED TWO DIFFERENT MAS, same symptoms. What I now have happening is a depression of timing upon partial acceleration. I can floor it and it goes. I've read in my Helms about a sticking TPS. I've never changed the TPS, nor even got it wet. YET the timing reduction/bucking, upon partial acceleration, the car bucks, then decides to go. Gas milage is the PITS! Alternator is new, so is the Ignition Control Module. Before I swapped the MAS (again, I tried two differnt ones), my car never exhibited any poor driving symptoms like this. Acceleration was great (regardless of 3.4 power or not, smooth pick up & car was fine). FUN PART No codes are stored, nor offered, right now. I do get the Code 12, yet no other code symptoms to help with this problem. Tips. IF no repsonse, it's ok, as I'm off to one with higher knowledge and better tools for testing all sensors while driving. Drag part is it's a long drive (you must always find an honest mechainc!) & this "smooth" driver of a Firebird ain't much fun! Gotta sort this problem out & I'm stumped!

See, this is the reason I am looking for laptop, and cable. No codes, but obviously something is fubar.

Could your converter have gotten plugged when your ignition was fubar. That causes poor acceleration, and crappy mpg I belive.

I'm sure you have checked vacume, fuel pressure, and timing.

Sounds EXACTLY like what my Red '85 was doing. Turned out I had 4 bad injectors. IIRC, I also had an intermittent code 34 before it went and started running like crap. Changed the IAC, checked the TPS voltage and set to spec, all new tune up, etc, etc, ...

Have an injector balance test done by the shop of your choice.

Let me guess... it starteddoing this "all of the sudden" ?

Beyond the all the sudden, this occured ONLY after I changed the MAS.
Prior to the MAS change, it purred.
This problem was instant.
ALMOST WISH I could obtain back the first MAS (that threw a code 34) I turned in for swapping.
I've left battery disconnected overnight, why not?
New Fuel pump (and all parts) too recent and I haven't had a vacuum problem to state.

Other tip before I leave before for this guys shop.
Recent stuff replaced.
New alternator (to cure the blowing out of Ignition Control Modules)
Same time, ICM replacement.
I have not touched any thing else nor gotten wet.
My connections are secure.

Inother words, prior to this, not a "true problem".
Car ran near prefect.
A code thirty four after the alternaotr swap, changed the MAF, this acceleration problem starts.

My gas milage was TERRIBLE until I replaced my 02 sensor. I was getin gabout 10-12 miles to a gallong (about 125 per TANK). Had no codes or anything, but had a dealership replace it because they said it was wet and bad. That's one thought and it's cheap.

As for the TPS, if you have multimeter you can check it. Unfortunately I don't have the Firebird, so I forget what the colors of the wires are. But you can read this thread I posted a while back, kinda quikly summarizes how I checked my TPS.

http://www.thirdgen.org/techbb2/show...&highlight=tps

See my hokey air inlet set up?
GUESS WHAT????
SOMEHOW air was ENTERING AFTER THE MAS UNIT!
AND because of that, it sent signals to the engine to compensate.
NOW the hole, which I couldn't see yet "the car computer sensed" caused the bucking & lousy milage.
I replaced my hokey air inlet set up with the original factory stuff & the problem is gone.
So gone I also took a drive with AC on, to test.
Not a bucking problem at all.
Drive perfect again.
HEY A NORMAL CAR WHAT A CONCEPT!!
FYI, the engine sensing system, was reacting so fast, the computer (ECM) couldn't sense or prcess the information to offer a code.
Which is why I had no code appear.
The answer appeared as was hooked up a Snap On tool to read everything on the motor.
My fan kicks on at 221* & off at 200*. I was very happy to see those temp numbers, confirmed.

Not all home made fresh air set ups are the right solution, I just discovered.