Hi, everyone. I am new here. I have been trying for days to figure out the problems on my 97 Taurus GL V6 3.0 with 86,000 Miles. Hope people in this forum can help me.
Problem: First months ago, CEL went on. I check cable connections then truned it off. It had not been on for a long time till 4 weeks ago on expressway. The code reading by AZ is P0303. I change the 1 spark plug (sold by AZ), car back on road OK. Week later I bougth another 5 plugs from O'reilly put them on. car ran fine. 2 weeks ago, CEL blinking on expressway. I took it to Ford dealer and paid them to check ($90). They told me the third and fifth misfiring, need new plug, coil, wire sets with a cost of $570. I take back change all of them myself. 1st start good, CEL not come on, but rough idle happen on 2nd start on parking lot (no CEL). I try to figure out why. After reading, I find 1st plug by AZ was the one for later model Taurus. Changed it same as other 5 (Autolite 764). All gaps checked before put on. 1st start and test run fine. After 15 min driving, I stopped engine 5 min later turned on and left it idling for about 5min, it started to stumbling slightly (lighter than with that 1 wrong plug in). But the CEL went on again. AZ pulled the code P0303 again. I cleaned IAC today and test drive for 15 min. as before, car and engine sounded beautifully, quiet and smooth. 2nd start ok too, drove back ok, then left it in idle then stumble again. Shut off, wait a few min, start again, stumble too. So far no CEL. these are not severe stumble, not normal either.
I read the posts on the internet. but cannot find a my stiuation. Driving no problem, red lights no problem, only warm idle kick off the stumbling. Idle rpm: cold start 1000+ then 800-900; warm strart 900, may cause stumbling. never stumble and stop run yet. Anybody can give me some ideas what to do next? Thank you!
finally, if vacuum leaks, should be only warm time? if engine has problme, why only on idle? I don't have any idea now.
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addition: I took the car out test again. Cold start ok, I drove for 30 min city local drive, 20-45 mph and sveral sotps and red lights. Everything went quite well. Back to my drive way, car sounded smooth, left about 2 min idle no problem, then shut off. About 10 min later I started the car again, engine felt some light stumbling. When driving, the car was felt hesitated to go. dove for a few min no CEL on, but not like when cold start.
Problem: First months ago, CEL went on. I check cable connections then truned it off. It had not been on for a long time till 4 weeks ago on expressway. The code reading by AZ is P0303. I change the 1 spark plug (sold by AZ), car back on road OK. Week later I bougth another 5 plugs from O'reilly put them on. car ran fine. 2 weeks ago, CEL blinking on expressway. I took it to Ford dealer and paid them to check ($90). They told me the third and fifth misfiring, need new plug, coil, wire sets with a cost of $570. I take back change all of them myself. 1st start good, CEL not come on, but rough idle happen on 2nd start on parking lot (no CEL). I try to figure out why. After reading, I find 1st plug by AZ was the one for later model Taurus. Changed it same as other 5 (Autolite 764). All gaps checked before put on. 1st start and test run fine. After 15 min driving, I stopped engine 5 min later turned on and left it idling for about 5min, it started to stumbling slightly (lighter than with that 1 wrong plug in). But the CEL went on again. AZ pulled the code P0303 again. I cleaned IAC today and test drive for 15 min. as before, car and engine sounded beautifully, quiet and smooth. 2nd start ok too, drove back ok, then left it in idle then stumble again. Shut off, wait a few min, start again, stumble too. So far no CEL. these are not severe stumble, not normal either.
I read the posts on the internet. but cannot find a my stiuation. Driving no problem, red lights no problem, only warm idle kick off the stumbling. Idle rpm: cold start 1000+ then 800-900; warm strart 900, may cause stumbling. never stumble and stop run yet. Anybody can give me some ideas what to do next? Thank you!
finally, if vacuum leaks, should be only warm time? if engine has problme, why only on idle? I don't have any idea now.
==========
addition: I took the car out test again. Cold start ok, I drove for 30 min city local drive, 20-45 mph and sveral sotps and red lights. Everything went quite well. Back to my drive way, car sounded smooth, left about 2 min idle no problem, then shut off. About 10 min later I started the car again, engine felt some light stumbling. When driving, the car was felt hesitated to go. dove for a few min no CEL on, but not like when cold start.