88 1.3 Sami. 76k miles always a towed motorhome car so 1/3 to 1/2 is tow miles. Starts and runs great. Passed smog test expect for high idle (1250) Found emission hoses hooked up wrong. Idle is OK now. Went back to finish smog test and was told it wouldn't pass because of exhaust smoke. No smoke on start up or when driving. If it idles for 5 + minutes it starts to smoke. The longer it idles the more it smokes. After driving a few miles I checked the exhaust pipe at idle and no smoke at all. Any Ideas? I did change to synthetic oil last week. Could this cause extra blow by? I need to put new front and rear main seals in it so should I just pull the engine and rebuild it or could it be a plugged PCV vale or something simple....I'm hoping.....

Instal a oil catchcan on the PCV and VC breather lines. A el-cheapo DIY version can be made from a small air/moisture trap from Campbell Hausfield and installed between the VC and the intake mani, all that oil is re-condensing on the intake mani walls and flowing into the combustion chambers.

My 1.6L 16v smoked upon start and after extended idle, it no longer smokes at all after installing the catchcans.

Still haven't gotten it to pass smog yet Any other ideas I can try.

You might try switching back to regular oil, even a heavy oil like 40 wt
to help with the smoking issue, I have heard that synthetic oil can start
the seals leaking because of it's extra special properties, and it might be
working it's way through someplace getting into the engine.

The last time I had the problem you are describing, my turbo was leaking
into the exhaust and smoking from heat, which smells different, almost a
Diesel smell as opposed to the 2 stroke smell like a motorcycle, I'm just not
sure how you could be getting oil into the exhaust without burning it in the
engine, that is unless you have a turbo on it

Wild