my 87 GTA with a 350 TPI have an intermitten weird trouble:

-I start the engine, it turn on then stall immediatly.

-I let the key on, unplug the MAF, then resart, it run(in safe mode because of the MAF unplugged)

-While running, I replug the maf, close the hood, runs perfect until i stop the engine.

SOMETIMES it restart normally, and sometimes i must redo theses steps.

Note 1: the check-engine i got is because i unplug the MAF, the pcm dont detect any problem with the MAF or anything else if i let it plugged.

Note 2: the trouble started gradually since 2 weeks, that began SOMETIMES by loosing power at 4000rpm, other day at 3000rpm, 2000rpm, 1000rpm, and now its not running at all when it do the trouble.

Note 3: i can eliminate gas/ignition problems cause the fuel pressure is perfect(vacuum/no-vacuum), i also changed the gas filter & put some new gas, distributor/wiring/sparks plugs is new since 2 months.

Note 4: i have an OTC scan tools plugged for studying the system, when i was loosing power in run, the mix goes lean, but the TPS working great, the timing advance is good, BUT the MAF value drop and jam when motor stalling. (15G/S)

I suspect the MAF sensor internal module random fault. (not the MAF by itself)

*When i unplug and replug the MAF, i think it force the system to reset*

Before changing this expensive part i want to make sure that is not another sensor, relay or a connection causing the trouble.

Waiting for your help guys, now i am not understanding...

 

any idea?