Low oil pressure on 99 jeep grand cherokee

misfires are more from problem injectors, low fuel pressure or injector wiring than from plugs
have a fuel pressure test done to check for problem pressure regulator , problem fuel pump , blocked m/dirty filter
one other area of concern is the EVAP system where the purge valve doesn't vent the tank properly and causes low fuel flow rates

Low oil pressure at idle can be caused by an engine with worn rod or main bearings due to (usually) high mileage . This however does not mean the engine is still not serviceable as long as the oil pressure is low only at idle. The pressure should at minimum get into the normal range at anything above idle speed.Not much oil pressure is really necessary at LOW speed. At low speed, as long as there is oil getting to the bearings, even at low pressure, you are OK. In a high mileage engine the oil pressure is often low at idle simply because the oil pump is turning slowly and cannot maintain higher pressure between the larger than normal crankshaft and bearing clearances. As speed increases the pump turns faster and supplies more oil and the pressure should go higher. Low pressure as long as it is only at idle is not a problem. However at higher speeds the pressure should be in the normal range. Such a worn engine can benefit from higher viscosity (thicker) oil such as 20W-50 in above freezing weather and 10W-40 in winter. That will increase idle pressure and the thicker oil film maintains a better film between the worn parts

Your oil pressure will increase and decrease with the speed of the engine. As long as your oil pressure increases, that's ok. The idle problem could be caused by a dirty fuel or air filter. I would start with replacing the fuel filter and check the condition of the air filter.

First check the oil level and top up as necessary. If the oil pressure is at 0 , then it would very quickly sieze the engine, that not being the case, it sounds like you need to replace the oil pressure switch/sensor, which will be mounted either on the engine block or on the oil filter housing. Hope this helps

check the oil descending unit or ur oil pump might b clogged up with soot, just some advice hope it works

installation is pretty much tighten and plug in as described. if gauge goes to 0 with engine off u should be fine. 15psi idle 40 psi higher rpm is normal. it is possible new switch not as as sensitive as old.

This is not necessarily an issue, but normal physics. I suggest remove your transducer and test with an external, known good, gauge.... Be sure the vehicle is at normal operating temprature....that will give the lowest pressure reading, as compared to cold engine.

idle solenoid or pump pressure
dirty fuel or filter
mabe throttle sensor

have a 2000 jeep grand cherokee with 84,000 miles. started having issues with oil pressure gauge going crazy up and down, beeping. had oil pump replaced per mechanics recommendation. didn't help won't hold pressure---only registers about 2. now they tell me i need a new motor!!! just bought vehicle less than 1 yr ago...had carfax clean report!!!!any suggestions?

how many miles are on the vehicle this usually happens when the oi; pump or engine is wore out.