My 1994 rx-7 smokes when first starting u after a winter nap. Should I be worried or is this normal. I have heard the O2 sensor going bad can cause this. Anyone else have any info on what this could be?

 

I think that the first thing a Bear does when it wakes up from hibernation is he goes for a good Dump!
If you woke me up after 4 months I would be puffing smoke too.
I say it's normal.I just started mine up 2 days ago..had a little "PFFTTTT"..
then smooth.

 

If you start your car when it's cool outside, it's perfectly normal to see some steam come out of the tailpipe as the car warms and rids itself of any moisture that may have condensed in the system over time or when it cooled from the last time you drove it. The idle should be smooth on initlal COLD start-up, the moisture/steam should have no peculiar odor (other than exhaust smell) and it should subside after a few minutes unless it's really cold.
Blue smoke = oil burning...Black smoke = too much fuel/rich. I could see a bad O2 sensor causing black smoke, but not 'white'.

 

Yup, its normal.

 

In my quest for a peppy rx7 I have had several white smokers. Its the water seals in the engine...could be the coolant channel through the intake but I've never been that lucky. Back in the day I added a product called alumaseal to the coolant, twice and it did help for a year or so. I have a new one that I am still hopeful for...I was swapping engines anyway so I took my whitesmokers flywheel off, broke loose all the engine bolts in order, then retorqued them in order to the max spec. and I haven't driven it yet as I am having some carb issues but that sucker was at about 3-4K RPMs and I have not seen the white smoke yet...knock on wood.

Mike