P0303 and Coolant

Carl · 2006-11-24T19:00:04+00:00

Jeep in question is my 2000 XJ. 4.0, Aw4. 95,000 milesOn the way back from Seattle today, I drove down a washboard road for about 7 miles, got gas and went to get back on the highway. Less than one mile after fueling, I get a CEL. Pull over, gas cap is tight, everything looks OK. Continue around 100 miles home, CEL solid the entire way. Fuel near home, 15.5MPG! I had previously gotten 21.1, 18.9, 20.1.Stop at CSK, pull the codes, and I get P0303. Cylinder number 3 misfire. Plugs are new copper champ's, Throttle body was recently removed and cleaned. Any ideas where to start looking?Also, I'm planning on changing the coolant soon. I have heard I can get the prestone heater hose tee, and flush it with a garden hose. Then drain the radiator thru the lower hose, fill the radiator with distilled water. Drain again, and refill with 100% coolant. Will this give me the right mixture?Thanks,Carl

Nov 24, 2006 41 Replies

Rate this thread:

bllsht 19 years ago

The readiness check doesn't test any sensors. It only shows you whether the non continuous monitors have run.

Vote

Outatime 19 years ago

Good call; this is only applicable to Chrysler OBD-I PCM's, not newer OBD-II systems with this particular scanner.

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required