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.
 
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.