86 commanche rough idle

[406sbc]

I have an '86 commanche with a 2.5L,5sp.4x4.The problem i'm having is that at an idle the engine will intermittently run rough,sometimes it will speed up on it's own and at other times the engine will stall.When engine runs rough i can clear it up by stepping on the accelerator,it will then be fine for about ten seconds until it idles rough again.I also have a problem with a hesitation when i'm cruising at about 40 mph and try to accelerate.Now here's what i've checked so far,I have done a complete tune up,I have 15 psi fuel pressure at the throttle body pressure fitting.I have installed a new throttle position sensor.I've checked the Map sensor,coolant sensor,egr valve and all tested good.My timing does'nt change when engine runs rough.When gasoline is poured into throttle body when running rough the engine speeds up,which leads me to think it's fuel related.I've cleaned the fuel injector.I'm thinking it could be the ecm,but i don't know how to test it.If you know how i could check for this or if you have any other idea's as to what could be causing this problem it would be greatly appreciated. Thanks

[MagicRat]

15 psi fuel pressure is a little low. About 35 psi is typicall for most domestic fuel injected engines, but I am not completely sure about your model.

The fuel pump may be bad, or the filter clogged or the pressure regulator may be faulty.

[406sbc]

Thanks for the reply.According to my manual 15 psi is normal for throttle body injection.I believe port injection requires around 35 psi.