2001 kia sephia help

[jaykwish]

I have a 2001 ki sephia with the 1.8 dohc engine. I'm thinking the piston rings are bad but I havent done a compression check. On startup there is blue smoke coming out of the exhaust and while driving accelerating takes forever. It also idles bad, but i have replaced the iac and there were no results. I have heard that it could be valve seals or the pcv valve. Any advice would be greatly appreciated.

[Strangerous]

Advance Auto Parts has 3 different brands of PCV valves for the '01 Sephia, they run from $2.77 to $6.59 in price.
To check the PCV valve before buying a replacement:
1) Locate the PCV valve.
2)Loosen any clamps holding the hose to the PCV valve.
3)Pull the PCV valve, be mindful that there is a grommet inside the hole that keeps the valve snug, it may be difficult to remove, but do not use pliers, as you may crack the PCV valve and have to replace it, even if it didn't need replaced.
4) While holding the PCV valve, Shake it... I'm not kidding... If the valve rattles when you shake it - reinstall it. If it doesn't rattle, it means it's stuck (open or closed), and should be replaced.
If the PCV valve is stuck open at engine idle, too great a quantity of spent gases are let through. Rough engine idling and stalling can be the symptoms.
If the PCV valve is stuck closed, pressure inside the crankcase can build up and the gases can force engine oil up through the breather and air filter causing excessive oil consumption and a fouled intake system.
With the symptoms you've stated, a stuck open PCV valve seems to be a descent guess, and at $2.77 to $6.59 for a replacement, It would be the first thing I would do.
Valve seals have a lot to do with excessive oil consumption, and by you not mentioning having to frequently add oil to your Sephia, I'm leaning twards the PCV valve as the culprit. If it's only smoke with loss of power... PCV and EGR valves can do crazy things... let's just hope it's a PCV valve.
Go and check your PCV valve, if needed replace it, and let me/us (the forum too) know how that worked out for you.

[ron1004]

Typically if the valve stem seals are bad then you'll see exhaust smoke when decelerating and shortly after start up, whereas leakage past the piston rings will normally cause smoke under acceleration.

If you do a compression test, and the pressure is low, you can squirt some engine oil down the spark plug hole, and immediately test again, and if there's a marked increase in pressure that confirms the piston rings are bad, but if you don't see a pressure increase then the valves are burnt cause the loss of compression.

As Strangerous advises check out the PCV first.