i have an 88' firebird 2.8L MPFI v6

I usually start the car and it runs fine, drive it for a bit (fine) then after awhile and sometimes i start the car i get a check engine light (i've done the 2,300 RPM check for a good 5 minutes at once and got nothing.), which reads Code 34 only, i check the MAF wiring with ignition on got 5v on signal wire, checked the power little above 12 volts, started the car hit the MAF and wiggled the wiring and connector and it did not stumble, i checked the MAF fuse it's fine and i changed it anyway. I also checked the connector to the relay and it seems to be good volts wise doubt its the relay since its an on/off situation unless im wrong? and the also cleaned the ground wire next to the fuse, then i checked for leaks in the intake system (none) and figured it could be a vacuum leak which i doubt i checked most the lines with water/eye inspection changed the ones i suspected and i have good vacuum, im not really sure on any other options, i doubt its the MAF Sensor itself because its not on from begining to end all the time it usually triggers as i drive every so and so times plus the MAF is pretty clean and has the screen on it as we'll, but the check engine light will stay on till i shut the car off, and sometimes i start it and it turns off or on depends how long it sits i guess, but once it triggers the idle stumbles at stop signs, lights, etc and feels like it's going to cut out.

i changed the TPS i have a voltage of .54-.58

changed air filter, pcv valve, and the essentials, also cleaned plantium, and torque to specs.

i also have a broken cooling fan overdrive switch i believe? left rear on cylinder head one wire switch but i doubt that effects the MAF, going to replace it friday.

and i want to adjust the idle since the rubber boot is missing (previous owner) but the in car tachometer is deffinity unreliable and i have ZERO clue how to hook my two wire hand held tachometer to the engine. I believe it should go on the ignition coil but i have no clue where...four wires + distrubutor coil wire.(my next step this and TPS adjustment.)

PLEASE HELP ME !!!
and if anyone knows how to hook a hand held tech to this beast let me know thank you

-Chris.

 

The DTC 34 is a MAF Lo error. It means that the ECM thinks that the MAF should be reporting a higher air flow then it currently is.

Let me bounce to the handheld tach first. Between the coil & the distributor is 2 wires, pink and a white. This has a connector on each end. The pink is +12 V (also coil +) to the distributor, the white is the coil dwell/trigger (coil -) wire.

Best bet is to get another connector piece from a JY and cut into it for access. Then temporarily replace the current one with the modified one for the tach connection.

Back to the MAF: in general the ECM uses the engine RPM & TPS value to decide whether the MAF is reporting OK. So an issue with either of those can cause a MAF error.

Even though the in-car tach is off, does it read steady? Or is it jumping all over the place? If jumpy, the ECM may be seeing the same thing.

The TPS is critical. Any open spots will cause problems. An analog meter on the TPS output while slowly moving the throttle can pick this up. The needle needs to move smoothly. Any jumping is a problem.

RBob.

 

the previous owner had the air box toward the front, i just placed it toward the radiator or right side for more air flow... and i checked TPS got .54 exactly, and adjusted the idle a bit... think that was the problem? the air box?

 

the RPM Guage in the car is jumpy, but my hand held tachometer is steady only jumps a bit not like the in car tach, TPS is brand new and is set at .54, and yes its smooth opening and closing...over 4 at WOT. The idle is set nicely, and the Intake housing has a new Air Filter, it's completely sealed and has zero pin holes, i also put plastic weld on the box joints to reseal what the manufacters suck at, and put the air box toward the radiator, because toward the front seems to not be getting as much air? not sure how it goes but i just now changed it and havent seen a code yet, waiting on that 1, i reset the computer after adjusting idle,TPS,that danged air box, and cleaning/welding the air box joints, started the car and no codes.

i also have a starting problem takes longer than usual at times, probably fuel pump relay? im not sure on that but after that it's running steady "SO FAR".

before hand i got a code 33 and 34 intermittently.