91 5th ave need help please!

[pureposion]

1991 5th ave with 3.3 liter V6, 153,000 miles on it. ok here is what happens when i start it it will run for maybe 4 seconds at idle then shut down, I can keep it running longer if i rev it at start and turn key off and on fast it will stay running but as soon as i leave key on it will die.
we tryed a diffrent map sensor still same thing i was thinking maybe cam-crank sensor could that be it ? any help please this is a young kids ride and money is very tight thanks. oh and how do i read codes on it thanks for any advice.

[purepoison]

got it to run it was the computer that the intake air flows past i put a used one on and motor runs great. now i have a new issue it will shift 1st -2nd and third but won't go into 4th it tries three times then stays in third automatic trans. could this be from changing the computer? should i have changed the compter on the passangers side as well? This shifted great before the running issue. thanks for any help.

[mikris]

Your transmission is in limp mode, unplug the battery for about 30 min and try again. You should also change the fliud with atf+3 or atf+4