2001 chevy s-10 2.2l flex, once engine heats up fully while driving, it starts surging and the oil pressure gauge starts wiggling each time it surges, will not do it under acceleration or when coasting, only when holding it at a cruising speed.

If the engine runs it could be a bad engine or the oil pump. If the engine cranks but doesn't run check the distributor drive gear as it also drives the oil pump. I hope this helps. Take care.

this is serious, do not try to start engine until you discover the problem. An engine does not loose oil pressure and then not start for simple reasons. The problem may be minor or it could be major.
Check oil and coolant levels of the vehicle engine, if the coolant is low, look for coolant on the oil dip stick.
If oil level is low, check top of engine and bottom engine for major oil leak.
Are you gauges analog, check to make sure gauge connection to engine oil sender is good. Gauge or sender could fault out.
The major thing to do next is verify the oil pump is still intact and works. They are driven by the bottom of the distributor shaft.
You will need to pull the distributor and get an tool attachment to drive the oil pump with and electric drill and watch the oil gauge to see if pressure exists. If no pressure -- possible broken pump.
There are other reason it will not start, ignition failure, not enough power to fire plugs, bad ignition parts.....

Check coolant inside the radiator add if nesesery
start engine for 10 minuts or let the gauge temperature in the midel
stop the engine and touch the lower radiator hose if it is not hot renew the termostat .if hot termostat is good
restart the engine and check if electiric fan run when engine about 200 Fahrenheit
let me know for more help

The first thing to do is put a mechanical oil pressure gauge onto the engine and verify that your oil pressure is actually dropping to 0 psi. If it is, pull the oil pan and check the oil pump pick-up screen for sludge (plugged). This is common in engines that have not been well maintained, If it is plugged, you'll need a new oil pump and pick-up screen (you may want to try this, then go after the overheating problem). Also check for ant particles of metal in the oil pan, if you see any chunks, you've probably spun a bearing and need a new engine. Also wiggle all the rods and check for excessive play (again, a spun bearing). Also, if the truck is a pre 2001 model, it's possible that the intake manifold pan gasket has blown out and the engine is sucking oil through the intake, allowing the engine to run low on oil. As far as the over-heating, it may be a separate problem, unless oil starvation has caused a hot spot and cracked the block or head(s). But it may just be a coincidence that both problems started at the same time. So basically, if you've lost oil pressure, you'll have to tear the engine down to the bare block to find all damage, but it will probably be cheaper to put a used or reman long block in

If the oil light and the gauge is showing low to zero pressure then you need to have the pressure checked by someone with a mechanical gauge to varify the pressure is low. Is the oil level at the full mark? I have seen where the oil pickup tube o ring gets hard over time and cracks which can allow the oil pump to draw in air and cause low oil pressure. If you run the engine with very low oil pressure for any length of time there is a chance that the engine may need to be replaced due to lack of lubrication. The chevrolet dealerships still provide very good service. Hope this helps.

First we would need to know when this occurs. Asuming the oil level is at the full mark!. If the pressure goes up during acceleration and down at idle when engine is fully warmed up, then this is normal. An engine requires 10 psi of oil pressure per 1,000 rpm ( ex. 20 psi at 2,000 rpm, 25 psi at 2,500 rpm, and so on ) . If the gauge is moving back and forth erratically at idle , i would say the gauge is bad. If it drops to 0 while accelerating I would say your oil pump is bad. If from time to time it seems to work and other times it seems not to work, I would say the oil pressure sending unit for the gauge is bad. If the pump failed you would start to here a Knocking noise from the engine in a short period of time. Use the above scenario's to narrow down what it may be.

Hi
have your oil replace with new and make sure it is the proper weight. In cold weather old oil gells up making thiker once it warms up the pressure will go down but is not protecting you engine.

likely oil pressure sending unit went out

your engine needs flushed .what is going on is idle has less pressure than driving and the sump is picking up dirt and debris but when you turn off or idle the debris falls off the sump.

Possible warped cylinder head, or cyclinder head gasket.