My owners manual for my 95 E320 wagon says to use premium gasoline, I was wondering what other people are useing?

 

Use premium as indicated in the manual unless you are in emergency to use lower octane only. Your car will run better and prevent possible valve damage.The car is designed to burn 91 octane.

 

I have a 1993 300E 2.8 been running it for years on 87 octane it rarely pings and then only going up a steep incline and floored to boot. The head gasket was leaking lots of oil this past winter (typical 104 engine) so when we opened it up I expected to see some effects of running it on 87 unleaded, surprizingly the valves and pistons looked good I'm still burning 87.

 

If the car is designed to run on premium, dont be cheap, put premium in the tank. Burning a lower octane will decrease engine performance, which would actually cause you to burn more gas than with premium. So you might think you're paying less in gas, which in fact you're paying more due to fuel milage/consumption. It can also create pits in your valves, or burn black deposits on your valves, which over time cause your valve train to not open or close properly, resulting in very poor engine performance, and possible further damage. It would be a pricey fix at that, especially if you pay a shop to do the work. Do yourself a big favor, only use premium gasoline.

 

Thanks, the reason i asked is that recently I ran into a problem one morning after filling the day before with 87 octane the engine would not start. Itwas a cold morning.After fiddeling with it for about 3 days(plugs, different engine computer, checked timing etc.) still would not start I towed it to my mechanic. He fiddled for about 3 days and reported there was no compression in the engine one cylinder less than 10 psi. He towed it at about 35 mph in drive and finally got it started. But it was really running bad. He reasoned the fuel was bad. Drained the tank and replaced with 91 octane. I have driven it 10k mileswith no problems.