1988 Cabriolet Rough Cold Idle

[bonedoc]

Hello! I have a 1988 cabriolet automatic. It runs well when it warms up. However, it sputters for a couple minutes until it warms up. Any ideas what may be causing this?

I should mention that the oil pressure warning light flashes and has a buzzer once I get above 2,000 rpm. I checked the pile and it is not low. I suspect a bad sender or the wrong oil type. Thought I should throw that in, as I’m new.

[bonedoc]

well, I replaced the spark plugs. A couple were a little loose! That seemed to take care of 90% of it and its below freezing today. I used starting fluid to test for leaks. When I spray around the intake boot, there is a small increase of idle. May need to tighten that up.

Now I just need to see why I am getting the low oil pressure warning when my oil is fine!

[timvw7476]

there are two oil pressure switches, one above the oil filter mount, one sticking out of the driver's end of the cylinder head. One is open circuit when engine is off, one is closed circuit when engine is off. If one fails it leads to the unending low oil pressure buzzer. Can't recall which is open circuit when engine is off but they are also separate color codes around the wire terminal. Good Luck.

[bonedoc]

Thanks! Looks like it’s the high pressure sensor by the filter. Jumped to ground and it shut the warning off. Will pick up replacement tomorrow. Thanks!

[vwoldbug]

Thanks for follow up

[volksworld]

ok just in case a new sender doesnt cure it(and make sure you get the correct sender as many parts books have them listed for the incorrect locations)...that system needs to see 30 lbs at 2000 rpm or it turns on the light...on tired engines you can sometimes band aid the situation by switching to 20w50...hooking up a gauge will let you know whats actually going on...the "real" cure can be bearings and an oil pump...iirc there was a vanagon switch that closed at a lower pressure as another used car lot trick...but if that engine sees 20 lbs at 2000 rpm it'll run forever so dont panic....as far as sputter if that car's digifant try a coolent temp sensor (round blue one in upper hose outlet)...if still CIS a warmup regulator (discontinued by bosch)...sometimes a CO adjustment will cure it if the initial setting is too lean it will run crappy till the o2 sensor gets warm enough to send a viable signal, then the computer can richen it up

[Butcher]

I believe the diesel oil pressure switch triggers lower. Fixes the warning light/buzzer but not the oil pressure problem.