I used "gunk" engine degreaser per directions, and the troubles started! I've done this before with no problems. (engine was cold when washed, never spray cold water on a hot engine)

Now the idle speed keeps jumping from idle (900rpm) to 2000rpm continuosly.
The car bucks (hard like it momentairly shuts off) at normal driving speed, but has strong steady acceleration all the way up to red-line on the tach (aftermarket "sun" tachometer). During deceleration the bucking starts and becomes the worst while attempting to hold a steady speed. I don't know if the weather is a factor but it has been raining hard since I washed the engine. This has been going on for 2 days now.

The car is a 1986 240DL with about 900k miles (not using any oil and has good even compression on all 4 cylinders).

I bought the car in 1997 and figured the age was catching up with fuel and ignition system components so I replaced:

rotor cap and wires (checked for condensation inside because of this problem and dried it out, didn't help)
Hall coil
main and in-tank fuel pumps
fuel filter
spark plugs (Bosch platinum plus 4)
fuel pressure regulator
timing belt (15,000 miles ago)
ignition coil
repaired most of wiring harness damage
coolant temp sensor
fuel pump relay
ignition switch
mass airflow sensor
fuel injectors
throttle switch
main fuse holder for the ignition ECU
air filter (last week)
tightened up the fuse block and applied dielectric grease there and all wiring harness connectors under the hood

any help here would be greatly appreciated before I'm forced to have it towed!