2.0L Engine: PZEV vs standard
 

Does anyone know what the differences are between the PZEV and the standard 2.0L engines? Looks like the PZEV car weighs about 15 lbs. more and produces a few less horsepower. What was added to the PZEV vehicle? Possibly something in the exhaust system? Any differences in the engine or tuning?

Trying to find out the same info. I think it is done by engine management and exhaust system mods. I noticed that the MPG is also less so what are we gaining. I have a Mz3 2L AT PZEV Touring Edition. One thing I noticed is that the car does not decelerate as soon as I take my foot off the gas. I have @ 1.25 sec. delay before the car wants to slow down. Most noticable when I lock the AT in 2nd in rush hour traffic and want to feather the gas and creep along. Does your PZEV do the same?

Mine has a manual transmission. I notice that MPG is significantly less than a friend's non-PZEV version of the same year (2008) and we do similar driving. Yes, the engine does seem less responsive as you note. I think that you may be correct: different computer programming (engine management) and exhaust change--this could be the added 15 pounds.

Just to mention, too, that sometimes it had some slight hesitation off the line. I wondered if this could be related to fuel, so I switched to plus instead of regular and the slight hesitation is gone.

I don't have a service manual which may explain the difference between PZEV and non-PZEV versions. Is the non-PZEV even offered anymore?

As a commuter, MPG is important to me. Seems that I cannot get higher than 32; my friend is getting 35-38.

Hope we can find out what is different...