1988 245 5x manual shift, about 175000 miles (odometer not working)

Problem: engine suddenly loses power while driving. I can be driving along normally when the engine suddenly refuses to respond to the throttle -- at least going no higher than, I would guess, around 1500 rpm. It does not stall. If I turn off the ignition and let it sit for a minute, it starts and runs normally. This has happened mostly after a sharpish turn -- i.e. accelerating away from the turn, the engine suddenly has no power.

The car was off the road for 2.5 years. I kept it on a float charger and started it once every two months or so, letting the engine run until it reached normal temperature. About a year ago I started driving it again. No problem until late last fall, when the engine began faltering and occasionally dying. Three service visits so far: fuel injection relay and air mass sensor replaced; and some fuel system wiring under the hood -- I don't know what -- re-routed in accordance with a service bulleting. Leak at inlet manifold apparently cured by tightening the nuts. Timing belt also replaced, though I don't see how that could link to the intermittent power loss problem. After each repair the car seemed fine. But this occasional power loss started again about a week after the new air mass sensor was fitted and the manifold nuts tightened.

Any advice would be much appreciated. I kept this car for my now 18 yr old son to drive, and want it to be reliable. Fuel filter clogged? Bad in-tank fuel pump? Fuel pressure regulator?

 

Try to hear if the fuel injectors are working ( you can hear a ticking ), they may be sticking.
Fuel filter, that could be too.
Try to get a reading off the new air mass meter, you never know.
How does it idle, fine or rough?
I don't think the fuel pump, they either work or don't.
Good luck