low idle when warmed up

[first time owner of a sho]

I have a 93 sho mtx and the problems all started one night coming home I was driving down the road and my car just shut off and wouldn't start for about 10 min it would just crank over but would not start then when it did on my way back home it died again but then I was able to turn key and start it but it was running really rough and died about 3 times the next morning I started it and it ran fine like nothing happened but I did notice that the tachometer jumps a little bit when warming up and when it is at normal operating temperature it idles really low like at 700 ram then will die any thoughts? It's my only car and I absolutely fell in love with it I'm not a lead foot and I'm very **** about anything that's happens to my vehicles I always check fluids and am up to date on everything I'm not very smart about working on engines but would really like some help and opinions on my sho thanks.

 

[sperold]

My guess would be crank position sensor (CPS).
Have a look and see if any coolant is coming out of the weep hole on the bottom of the water pump (dentist mirror maybe). It can drip onto the CPS and shut the car down. If there is a water trail, it is your water pump. No trail, it is your CPS failing.

Smaller possibility it is the Cam Position Sensor, and you can verify that by noting 3 or 4 attempts to start in the morning, and if you unplug the sensor harness, the car will run correctly (after 3 or 4 tries to start it).

 

[first time owner of a sho]

So it hasn't died the last few days it actually runs great but when it warms up it has a low idle around 700 rpm could that be the cps failing and where is it located ?

 

[rubydist]

crank position sensor is on the crankshaft, behind the damper pulley and the timing belt sprocket. they can die whether the water pump leaks on them or not, so that is a candidate. it is a candidate because they can often fail when hot, but work fine with a cold engine. generally, the crank sensor on its way out just results in the engine dieing, rather than running rough.

the cam position sensor is another candidate, it is on the front (right) end of the motor on the rear-most cam. the cam sensor is responsible for driving the tach, and a sick cam sensor can cause the engine to run rough and/or die, so with your symptoms it is also a candidate.

idle around 700 is where it should be, so no issue there.

 

[itwonder]

Search the forum for idle reset procedure; give that a try.