surges 30 to 50 mph

[swordfish]

Just got through rebuilding 94 metro for my father.Only problem is at mid speed while holding the accelerator pedel steady the acts like it runs out of gas for a fraction of a second. Above 55 to 70 it runs great so it is not a gas filter problem. The only thing I have adjusted is the screw that holds the butterfly open. (idel screw on a carburator) and a screw with a rubber plug covering it going horizantal toward the front of the engine that my sorry service manual said was the idel screw. it did not seem to do much for the idle. My father is 82 and 45 is his speed,so guys I need some help. Thanks

[swordfish]

The problem was a vacum leak. A hose that plugs into the bottom of the air cleaner was disconnected and plugged. The idel adjust screw ( on a carburator) was returned to it's orginal position and the idel screw under the rubber plug was readjusted. The car now runs perfect. 94 3cyl metro

[hvdragon]

What to check when the engine surges:

Leaky or loosely connected high-tension cord
Faulty spark plug (excess carbon deposits,
improper gap, and burned electrodes, etc.)
Vacuum leakage
Variable fuel pressure
– Kinky or damaged fuel hose and lines
– Faulty fuel pump (clogged fuel filter)
Malfunctioning EGR valve
Poor performance of MAP sensor
Faulty fuel injector