I am having an intermittent check engine light on my 90 306. When the car has been in use for a while after warming up, the light will come on. The codes I pulled were 63, tps voltage below min, and 31, evp voltage below min. what i did tonight was, unplugged the tps, put some dielectric grease on the plug, replugged it, ran the koeo self test again, passed (except for 67). i started it up and the engine light promptly came on again. i really hope i dont have to replace my injector harness...ive already dielectric greased the black and white plugs on the back of the intake. do i have bad sensors? it only seems to do it when hot. also, i ran the test with the tps unplugged and it gave the same code. it seems like maybe i have intermittent reference 5 volts, but ONLY to those two sensors. it's friggin weird.