Cold Start - Rough Idle And Blue Smoke ?

fiveoho

15 Year Member
Apr 28, 2005
1,958
16
69
TN
i've noticed this on my 00 gt the past two times i have driven it. it only seems to do it on a cold start. the car starts up and idles very rough. a good puff of blue smoke as well. the erratic idle lasts maybe 2-3 min then clears up and the car runs fine. the smoking only lasts 20-30 seconds on initial startup. smells of oil. the two mornings it has done this has been pretty cold. the car is not a DD. on average it gets driven once a week.

the 'service engine soon' light has been on prior to this. there are 3 codes -
p055: evap leak/gross leak/no flow
p0153: oxygen circut slow response bank 2/sensor 1
p0442: evap small leak

fuel pump was replaced a while back and some time passed after replacing it, the light tripped. then, it was just the evap codes. i assume we binded up gasket maybe around the filler neck or the gasket on top of the tank during the install. but could a failing O2 sensor cause the rough idle and blue smoke? after the initial startup, the car runs perfect and no smoke whatsoever.

thanks in advance for any advice.
 
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Sounds like you have worn or bad valve seals. If your car sits overnight, or for a few days your seals are allowing some oil to seep through into the combustion chamber, that's usually why it only smokes for a few minutes.
As for your other codes i have also had the same ones, and never had any running problems from them. Get your evap system checked, could be something as small as a pinched hose. My problem was the fuel filler grommet. take your Stang to a local shop and have them run a smoke test.