Hey guys, my 94' civic coupe is idling really rough. It normally sits around 800 rpm, but had been dropping to 400-500 rpm and shutting off occasionally. The oil light also comes on during all this, but it shuts off only when I depress the gas pedal. Any ideas on what the heck this is?

Car is bone stock as far as I know. The guy before me did some really funky wiring that melted the headlight wires. Who knows what else he did.

 

be careful of running car too much with oil light on. it means your pressure is low.
check oil level and for leaks.
check coolant and oil for cross contamination (oil in coolant coolant in oil)
what is the weight of the oil that is in there currently?
I'm currently troubleshooting burning oil and when i put a quart of MMO in my car prior to oil change i got a low pressure light to but only at idle below 600.
my light came on because the MMO thinned my oil too much. in conjunction with the low idle.

as far as the low idle im not the best to help with that but on my last civic and this one they both fluctuate. but its low on my list of things that need attention right now.
I know there is a couple things that could cause low idle, sensors, throttle cable adjustment ,etc. Ill eventually figure out my idle fluctuation during the process of replacing all the sensors and restorations i have planned for my eg.

 

A lot of factors causing that but it looks like low oil pressure to me. May be due to worn bearings? Best to check the oil pressure switch too.

 

Rent (free at most auto parts stores) or buy an oil pressure tester and test oil pressure. Harbor Freight has one: Engine Oil Pressure Test Kit
Oil light could be due to a faulty oil pressure switch (located near oil filter) or harness contact may be loose. First disconnect and clean both the oil pressure switch connector and the wiring harness connector may need to slightly tighten harness connector.

Idle may or may not be related to oil pressure. Remove and clean the throttle body and IACV or FITV (whichever one your engine has). Watch youtubes on how-to-clean. Could be (weak) spark related too so, test spark as well.

 

Nothing wrong with the oil light coming on when the engine is turning so slow that it is about to stall.

Start by cleaning the IACV. Also make sure the air passages in the intake to and from the IACV are clear.

 

5w30

 

Okay, thanks. I'll try that out and will get back with you.

 

Like mk378 said, when the car is about to stall, the oil light will come on naturally.

That indicates your oil pressure sending unit is working properly.

If your oil level is fine, and when it's at normal RPM the oil light is off and it comes on when you first go to start the car (oil light works) or stall the car. Then you aren't focused on oil, you should be focused on your idle problem.

If your oil light came on when idling at 750 rpm, then their would be serious concern about your oil system. But from your description, it only comes on when you first turn the key on, and when you stall the car.

 

Well, I did find two leaks. Oil pan gasket and value cover gasket.