Crazy 1988 Mustang LX issues.

[shanetrain2001]

Here is a good one for someone to take a stab at before I start throwing money at it. 1988 Mustang LX 2.3. At start up the engine sounds fine and runs very very smooth. After the engine runs for 5-10 minutes, it will begin to sputter, lose idle, and a knock can be heard in the lower region of the block and then it dies. But once you start the engine again, it will repeat that process. The engine has no power when in gear, but it does not nock when revving the engine, or in gear. Are there any sensors Im not aware of that can cause this behavior. When my girlfriend first reported the knocking, I figured it was time for an overhaul. She recently had a new timing belt put on, about 6 months ago, and the car had been setting this whole time. Is there a special timing sequence for this engine that the previous mechanic may not have heard of, or do I just need to yank this motor out.

Thanks

[351wStang]

If you dont get a check engine light or anything then you may have to tear into that motor to find the problem.

[82Stang]

It would help having a scan tool to diagnose some of this, but in any case, look into the CPS Crank/cam position sensor. Maybe that would cause some of this.

[351wStang]

I dont think there where such sensors on that era mustang.

[Turbokid15]

Too old those sensors are not on that old a car.

[fordtrucksonly]

Sounds like your loosing fuel pressure. Maybe failing fuel pump?

[82Stang]

My mistake, sorry.

The fuel issue sounds good. Fuel pressure regulator? Pump? Or could it be related to an O2 sensor problem?

[shanetrain2001]

Thanks to everyone who responded. I ended up tearing the engine down and at first saw nothing wrong physically to the naked eye. But then again, my shop at night is not the brightest in the world. Took it to my machinist we have used over the years, with all the parts scattered in the bed of my truck in broad daylight and within 10 seconds he seen the issue. The #2 piston had a hairline fracture on the bottom of the skirt all the way up to the to the pin. I say hairline fracture because it was so small and I missed it because I was busy looking for something major. But I guess that just goes to show to never rule at the small things, and if you have a great machinist, then keep him. Thanks again everybody for suggestions. You are appreciated!