1996 Lesabre Engine misfires, hesitates up hills Stalls once

A MAF device from your local auto store is only about 90.00 and not so had to replace. If you are recieving a P0102 then you do have an air flow issue. First try checking to see if you have a vacuum leak. Get a can of Starter Fluid and spray it around your vacuum hoses and base of manifold. If there is a substantial leak the RPMs will increase for a moment. Fix leaky hoses first as this is cheaper.

Have you used an oil based airfilter like K&N. If so over-oiling can cause contamination of the MAF. Use an electroinic cleaner (Radio Shack) to spray on MAF device to clean it. This is also a cheap maintance test.

A tune-up is always necessary if you have waited a long time.