Just took my car out of storage about 2 weeks ago. It's an 1989 firebird formula 350 with 71000 miles on it. When I'm going about 20mph and I stomp on the gas, the car will down shift to first gear like it should and then it dies out. It only does this while I'm already moving and with the head lights on. If I drive during the day, the lights are off and there is no problem. If the lights are on and I stomp on it from a dead stop there is no problem. When the car dies out there is no Service Engine Soon light. There is no problem at higher speeds when the car down shifts to 2nd gear.

Just to be clear, the car dies out only when the head lights are on, and the car down shifts to 1st gear at 20mph.

 

Well, the car is still doing the same thing, but now I'm getting a service engine soon light and I checked it with my scanner and I'm getting a code 34 which is Mass air flow sensor. I pulled it out and every thing looks good. I know they cost some coin because I put one in my old iroc-z and it was like $240 for a new one from GM about 10 years ago. Any electrical checks (OHM checks ) that can be done on the sensor to prove it's bad.

 

Let's move this to "3rd Gen/L98 Engine Tech", where you might get some help.

 

Can you swap one from another car that is running fine?

I see you have another Firebird, thats why I asked.

 

Thanks for moving. Sometimes it can be hard to decide where to post.

 

No, my 350 firebird is TPI which uses a mass air flow sensor, and my other firebird is a TBI which uses a Map sensor and so does my 91 camaro with a 350.

 

Is it still doing it

 

As of Saturday night, yes it was still doing it. Only at 20mph or close to that and when the gas pedal is pushed all the way to the floor and right after it shifts into 1st gear. Only when the head lights are turned on which I can't make the connection between the two.

 

does it do it with the parking lights on with(no headlights)?

 

I don't know. I never thought of trying that. I'll check it out this weekend and see what happens.

 

You might also check your amp draw with the lights, radio,flashers on. You might also have a bad ground. I know it my sound silly but I also had a similar issue years ago with my Chevelle and it turned out to be a a dirty ground connection.

 

Thanks, a few more things to check this weekend. However the weather forcast is rain for the weekend and I really don't like taking the car out in the rain.

 

well what happened. any more info

 

Sorry, been very busy doing yard work and have not been on the computer in a while. I've been driving it the last few days to work, and I have not had a problem with it. Everything seems to be normal. But, this is only temporary like most problems, I'm sure it will come back.

 

im gonna throw this out there and hope it lands you on a fix.

my 89 formula had a headlight issue once. i was going to a friends place that does local fab of F stuff like SFCs and such. for what ever reason my switch started buzzing so i pulled over and checked things out. everything seemed normal so i went and again as i hit the rumblers on the shuolder they acted up again. finally i gave, the lights gave me a break and i went home.

bout a year later i had a wper issue. thought i had a weird surge and it poped a fuse so i replacd it no biggie. shortly later it did it again so i replaced it 2 more times and gave up. luckily i had much rain x on the windo so i had no issues.

going home that day the lights acted up again as i was almost home. i backed the car in the drive and ripped the dash apart. after i had the switch dangling i went underside to see what i could find. with the fuse block pulled down, head in the floorboard and feet in the headrest i started poking around. dunno what told me to but i rolled this hue chunk of harness around that is just right of the fuse block as your looking up under the dash.

lo and behold there were 4 wires that had the insulation rubbed off from the lower dash support bracket that is next to the fuse block. check this area and see if you have something similar going on.