2002 Astro with random misfire (P0300) -replace distributor?

all those sensors are bad or there are some bads wires, chunks of wiring harness or bad grounds. older vehicles often do not suffer from a new trifecta grounding system. batt to engine, engine to frame, frame to batt. bad grounds can look good.

hell i found a bad ground on my car after the windshield washer stopped spraying. traced it down with a power probe. the washer motor was getting power but, not ground! i Ted off the ground wire adding a left straight ot frame not only did the washer spray but, the blinkers were no longer blinking fast. granted that was a new beetle.

might not be your problem but never hurts to service and add grounds. infact i should do the same on mine

named-user said:

Appreciate the advice, thank you. Will start checking the grounds and see what resistance Im getting (if any). Also going to change the fuel filter and run Redline cleaner cause I figure I may as well do that


Edit: Today gave it a check. MAF ground reads 20-50Ω (depending on where I check, frame, battery post). Intake air temp sensor ground reads 250Ω though which seems high. Any ideas where this ground is attached? O2 sensor ground reads near 0Ω

Also checked voltages. MAF is getting 12v and 5v. IAT is getting 5v. Manual says to whack MAF with a screwdriver or something with engine running and check for stumble; will have to try that

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scan the frame and body work for wires bolted to it, if you find any, remove it and sand the eyelet and the body/frame where it attaches, rub it down with some dielectric grease and put in back on, snug it up. the grease will mush out and fill and air pockets and voids with grease to displace moisture. if it's old and work maybe replace the wire or ground strap. maybe even trace it back to see where it goes?

in the case of my bug like mentioned above i could see the washer motor had positive.