I just purchased a used c230 1997, the check engine is on, Checked it at an independent shop, the print out that he handed to me stated p0170 is the OBD II code. At AutoZone I saw it reading p0170 and p0136. II am not sure if they are two different problem or they are related. Any idea will help. The tranny  shift harder than normal.

Your PO 170 code has to do with "Fuel Trim Malfunction".  Some of the causes for this code are as follows:

1.  Intake air leak

2.  Injectors

3.  Fuel Pressure Regulator

What's happening is your engine computer is not able to compensate for an extremely rich condition or lean.  Basically it's maxed the limits on fuel trim for whatever problem you have.  I would start with an intake leak (vacuum leak) somewhere on your engine because that will also cause the erratic shifting your talking about.  Let us know what you find!!

As I re-read your message I realized you have a code 136 as well, this is related to a faulty 02 sensor of which will cause a code 170.  Forget everything I wrote earlier, your 02 sensor is bad and needs replacing.

When you check the O2 sensor, make sure nothing foreign is on it around the threads. I've heard so many times of "technicians" putting a sealant, anti-seize, or some other fumy gunk on them. The sensor will "read" the fumes and go beserk. They should be super clean with nothing on or near them that gives off fumes. They are also very easy to damage if dropped or banged around during installation.  

Thanks Dale

Did you experience any of the trans-shifting problems that I stated above?
What is a good reading range for the MAF for this car, what is a bad reading range for the MAF for this car?

while the car was running:
I saw  the MAF .69lb/min I don’t know if this means any thing...Is the range in Volt or Lb/min

I saw the O2 ranging btw .1v and .9v. , I think this is good .

I can tell you the transmission in my wifes C230 shifts really hard into second all the time, hot or cold so I wouldn't be too concerned about the tranny just yet.  First thing is to get rid of that PO 136.  If your fuel trim is getting confused I can see how it would effect everything from shift quality to gas mileage. 

The MAF readings your seeing don't really mean a whole lot because it's only reporting air flow and temp. to the ECU.  If it was bad you would get another code so I would stay away from it for the time being and focus on what the computer is telling you and that's the 136.  I've been in your position before when it comes to troubleshooting problems, after replacing a lot of good parts you find out the computer was right all along so dig deep into the O2 sensor code and get back with us.......When you've fixed that I believe the other code will go away and you'll be back cruising on main street again!!!

Your range of .1 to .9 is fine although I would like to see it up around 1.3v.  It might be time to bite the bullet and install a new O2 sensor before we go any deeper with this problem, and that's only if your sure you don't have a vacuum leak to the fuel pressure regulator or anywhere else on the engine.  A normal vacuum reading at idle is a steady 17 to 18 inches.

how to check for anormal  vacum reading and which part control the vacum on this car. thnaks