Runs great cold, lousy after warm-up
I just replaced the engine (original = 180k w/ thrown timing chain and worn out, new = 115k w/ unknown history) on my 94 5-spd 4x4.
Everything went pretty well until the very end. I set the timing on the cold engine and it ran very smooth. After warm-up, however, it runs rough and barely idles, sometimes stalling. If I let the truck sit and cool off, it runs well again until it warms up.
Plugs (gapped), distributor cap, rotor, exhaust manifold gasket are all new. I checked and adjusted all the valves.
I have swapped several parts from the original engine onto the new one with the same bad performance: throttle body (w/ TPS) and two coolant sensors on front of intake manifold. I also listened to the injectors with my stethescope and they all sound fine.
I get no CEL.
A helpful Yotatech member has suggested a bad EGR valve.
Any other ideas or suggestions?