Re: M/C solenoid......?
check all the sensor wiring.
a temp sender that is shorting out will cause all sorts of weird problems. if it runs good when cold but then starts running progressively worse as it warms up, then i'd check to make sure that the temp sender wires aren't shorting together.
O2 sensor will also cause it to act all wonky after it warms up.
check the hose to the MAP sensor- a bad vacuum reading will cause the computer to freak out.
check that the TPS voltage is good at idle, and that it kicks out a smooth signal as you open the throttle.
and finally- check for vacuum leaks. grab a 13mm socket and snug down the throttle body bolts, and make sure the hoses to the PCV valve and brake booster are in good shape.
this is all basic stuff that costs nothing and only takes a little time to check.
you don't plan sincerity.
you have to make it up on the spot.
wanna hear about 20 years ago when i was too smart to know any better?