1995 Oldsmobile 98 • 139,500 miles

Car starts and runs fine. Driving down the highway at 70 mph and will stall out. Was starting right back up but now isn't until I pull the wiring coupler off of the mass air flow sensor. Replaced yhe MAF sensor with no results. Am assuming it is a sensor of some sort since it will still run with MAF disconnected. Any ideas? Thanks!

Have you checked the map sensor? Have you checked the fuel pump pressure?

No I can hear the pump kick on and since it will run for about 20 miles before stalling and will run after I take the wires off the MAF that fuel pump is not the issue? Also cannot check codes as this vehicle Is obd 1 but has an Obd 2 connector. I did pull the idle air control and have cleaned it. Pulled the air intake and cleaned the honeycomb screen on the throttle body.

Also have replaced some of the vaccum lines that I found were bad.

I have seen issues like this that were caused by a bad map sensor and a lazy fuel pump. The pump may not be keeping up with the demand at higher speeds.

OK thanks will do some checking on these. Is there any test to check the MAP?

I always do an active test. While driving, my scanner provides real time information. I can watch how it reacts.

Also car will start and run fine again after sitting over night. Reconnect the MAF but will also die while just driving around town at 35-40 mph. Seems something is heating up and then not operating properly? Will take it in for a fuel pressure check.

You can test fuel pressure yourself. It's easy. There is a how to video and directions on our homepage under the DIY section.

Fuel pressure at the rail is 45-46 kbs which I believe is within specs. Have changed plugs and wires with no change. TPS and idle air control valve are new also.