I have been trying to diagnose a bunch of problems with the way my car runs. Its a 1992 190e 2.3. Poor power, stumbles on acceleration, I was looking at fuel injection but thought I might have a vacuum leak so I bought a vacuum gauge. At idle the needle oscillates rapidly between 10 to 13, I think it should be over 15. It stops oscillating and goes up as you increase speed. Troubleshooting guide says its worn valve stem guides. Can anybody second this opinion, or are there other possibilities??
Thanks