Help you guys. Im driving tonight to my sisters and im waitng for the light to make left turn, Just as i let off the clutch to go the engine stutters,the engine light goes on and the car starts to make a put-put sound as i whimp along the turn, I barely make top her house two blocks away. I pop the hood with the car still running. I see nothing out of the ordinary. i check some hoses,vacuum lines, and connections with a flashlight.
It idles fine, the oil pressure is stable and the engine isnt making any abnormal sounds. So i turn it off. wait a few, turn it back on and the engine light is off now. So I try to move her abit forward and Bam! it happens again, Wngine light on, stutter-stutter-put-put sound and no power. What could this mean?
I just put new water pump gakets on and nothing is leaking. I left the car at my sisters house. I dont want to drive like this. Help a brotha out!

car has 187,000
vacuum gauge reads 15psi
air fuel read stioch

 

take the AFM out and check the terminals for resistance...use the FSM for specs and how to

 

With my car it ending up being the metering oil pump. When the pump goes out the computer goes into a safe mode so you don't put to much stress on the engine if the MOP is inoperative. It sounds to me like what you are experiencing. Just check the internal resistance of the pump and the position sensor.

 

Also check all intake ducts for any leaks.
I see you have a '91, so pull the ecu codes to see where to begin looking.

 

on an s4.. what codes would cause limp mode without throwing the CEL? my cars been doing that on the freeway.

 

thanks, for the input. im going to check the AFM. Why would leaks become so evident in my air intake. And how hard to put a metering pump in.

 

what position sensor am i looking for? any hep on the MOP would be cool. thanks

 

The MOP is fairly easy to replace, one of the mounting bolts is little difficult to get to but that is it really. Just be careful with the oil lines when you remove them, they will be very brittle and a pain in the butt if you have to replace them. The position sensor is mounted on the pump itself, the connector is the 3 wire connector by the altenator.

 

TPS or OMP.

 

okay guys get this... i tried to check the codes, but i have none! but after futher inspection i hear a hissing sound in the VDI soilinoid area when i manipulate the throttle. vacuum leaks dont throw out codes? heres whats what:
driving is smooth up until 30mph.
oil pressure stable.
A/F stioch
RPM 750 at idle rock solid
1/2 tank of gas
check engine comes on at 15 mph

any ideas?

 

oh yeah doing the poor mans compression test i get three good pulses from both rotors, and no fluids leaking.
Help me Obe One, youre my only hope!

 

Get yourself a can of starter fluid and spray around while it's running. If it makes a drastic change up or down in idle, you've found an open air leak.

Vacuum leaks usually make for a shitty idle, but won't pull a code of any sort. They also shouldnt really affect driveability at all, unless it's quite a major leak.

 

youre right, i thought my idle would suck , buts its steady. I hear the hissing only when i throttle up. its it possible i have a bad solinoid or something?