Exhaust Smoke and Hesitation-Help!

[mlashun]

After getting an oil change and Grease Monkey telling me that I needed my Valve Gasket Cover replaced, I just took my 1995 Nissan Sentra GXE to Dick Smith Nissan and had it replaced. Well, after having it replaced, my car started hesitating and smoking out of the exhaust. I took it back for them to look at it and they said that one of the spark plugs was not completely in and that they double checked that. After leaving and returning to work, it happened again. I drove it on the next day to ensure I wasn't hallucinating and took it back to Nissan when the hesitation and smoking continued. Nissan said they couldn't find anything wrong with it and they cleared the vacuum hose to make sure it didn't have any debris in it, but that my car did not smoke for them after they test drove it. Well, it happened again to me and I decided to take it to the mechanic I use for small jobs. They replaced my spark plugs and adjusted my timing after having to find the timing marks which were not visible to them on my car. After I drove it home and around a little bit, it seemed to be fine, but then the hesitation started again usually after I stopped or slowed down and started to accelerate again. Each time it did this, it acted as if it wanted to cut off and it would smoke again from the exhaust. I took it back to the mechanic on Monday and they didn't get back to me until today to tell me that they adjusted the timing again. I feel sort of uneasy about getting it back not knowing if this is going to happen again. Any ideas on what's going wrong all of a sudden with my car just from having my valve gasket cover replaced? Any feedback would be appreciated.

Thanks

[mospeed1]

what color is the smoke...black gray.white?

[mlashun]

The smoke is gray and only appears when the car is hesitating and starts to act like it wants to cut off. Would this have anything to do with the timing on my vehicle?

Thanks

[vvalarie]

IM having pretty much the same problem except my smoke is definatly black. replaced plugs wires float 3x (1 cali emmisions ) nothing works bought carb kit. nope, what now? my mech is stumped and just says replace carb but im not so sure thats going to do it. I got kids so im driving it to work anyway. it boggs down dies out smokes black any other suggestions PLEASE.

[mlashun]

VV, Since I got my car back the last time, it's done the smoking thing twice (on the day I got it back) and hasn't done it since. I've been driving it for about 3 weeks now and it's doing fine. Seems my ignition timing was wrong and this sounds like a pretty difficult thing to set correctly, but thank the Lord, mine is fine. It doesn't seem to have quite the pickup it did before but that could be my imagination. I won't be driving it long distances anymore, that's for sure. Still not sure I trust it. But you should have your mech check the ignition timing as that seemed to solve my problem. Thanks for responding.