S10 Trouble

Can Anyone Help. We Have Put All New Sensers On This S10 4x4 1986 2.8 A Fuel Pump A Computer New Timeing Chain An Gears. It Still Will Not Idle. When You First Start It It Will Do Good For About 2 Minutes. Then It Starts Idleing Up An Down Then It Finally Dies. Does Anyone No What Could Be The Problem. We Have Worked On It For Last 2 Months. Took It To The Chevy Dealer Had It Put On The Machine An They Didnt Even No. It Was Way Out Of Time So We Did Replace The Timeing Chain An All That. But Still Wont Idle Right. It Kinda Loaps Up An Down After It Gets Warmed Up. Anyones Help Would Be Greatful At This Time. Thanks Des10

Some ideas might be to check:

- all vacuum hoses etc(can look ok, but be internally collapsed)
- ignition module/coil pick up
- TPS (Throttle position sensor)
- IAC solenoid (idle air control)

I have also sprayed carb cleaner around throttle body and intake when running. If idle changes for the better while doing this, can also mean a leaky intake, hose etc.

Hope this helps.