96 Civic EX Auto

I will run the car say 15 mins, go into a store say 10 mins come out and it idles rough for about 10 mins or so, sort of shakes and I can hear the tail pipe shaking. The idle seems to be steady just rough, like a shake.

No CELS

Recent plugs, wires, cap and rotor a little older.

 

Do you have a cluster with a tach?

 

Yep all EX's do, the idles seems to be right around the 700 point within spec, no fluctuation like signs of a bad or dirty IACV, only happens after running and then restarted.

 

I don't see a problem.

 

Still having this problem, basically shut it off and is chugs when restarted, possible fuel pressure regulator?

 

Sounds most like symptoms of a bad TW (also known as coolant temperature sensor) - usually if it is bad enough to affect running it should throw a code.

It's the two wire sensor located right under the distributor - they're easy enough to replace, and if you can find a known good one and swap it i'd say try it.

 

BTW the TW/coolant temp sensor is #13 seen here:



Just a place to start.

BTW:

A fuel pressure regulator is a mechanical part, and likely would not cause come and go symptoms.

 

Thanks, I always though that was more related to cold start ups, not warm ones.

Can you get away without draining coolant, I assume some will come out.

Do you know the socket size? I will have to get a deep socket for it.

 

This is where i'd place my bet!

 

I just did the ECT anyway, got it cheap. I will give it a few days.

When I took it out I did not drain the coolant, a lot more coolant came out then I thought would.

 

 

could be bad engine coolant temp sensor not the gauge sensor.
test while on car to avoid air in the system.
haynes manual has a temp/resistance chart.
check bookfinder/allbookstores/ebay if you need a cheap haynes.