I put in regular unleadead by mistake my car takes premiu...

Q: I put in regular unleadead by mistake my car takes premium

asked by on January 04, 2017

My car is hard to turn over sense I put the wrong gas in it. I made the mistake by putting unleaded study premium. What can I do about it

My car has 143000 miles.
My car has a manual transmission.

Your vehicle will start and run well on both regular and premium fuel unleaded. Premium fuel is stated as "required" by Mercedes Benz simply because premium will maximize the performance, fuel economy, and possibly service life of the engine. But, an occasional tank of regular fuel is harmless, particularly if the knock sensor in the engine is working properly. In all events regardless of what fuel you use the knock sensor adjusts the timing on your engine so that varying octane fuels (e.g., regular versus premium) can, in practice, be used. Consequently, the hard starting condition you are experiencing is caused by a fault in either the car’s starting system, the ignition system, the fuel system (fuel pressure and amount), and/or the air induction system. If you request a hard starting diagnostic the responding certified mechanic will identify exactly where the problem is and will give you a repair estimate.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Engine turns over, cannot run

Hello. I would have the system scanned for any codes and have them diagnosed to see if they lead to possible cause of the problem. Have the fuel system also checked for any problems when the problem happens to help...

Low gas mileage on 1997 GMC K1500 Suburban V8-5.7L

Hello. We will be happy to help with your 1997 GMC K1500 Suburban. There's likely a combination of reasons as to why your MPG has so greatly declined. I suggest that you have a technician inspect the following items and...

Power window coming off track.

Hello, to see why the window is coming off track, the door panel and water barrier will have to be removed and view the operation of the window to see the cause. You may need the aid of a mechanic,...

Related articles

How to Buy a Good Quality Fuel Pressure Regulator
There There are all kinds of shapes, styles, and capacities of fuel pressure regulators – from fuel-injected applications to carbureted vehicles and diesel-powered and E-85 engines. The fuel pressure regulator works with the fuel injection system in order to send...
A Buyer’s Guide to the 2012 Mercedes Benz S-Class
If If you’re looking for a vehicle that delivers top-of-the-line features, comfort, performance and safety, all while showing off the prestige of the driver, the 2012 Mercedes Benz S-Class is your choice. Key Features With Active Body Control and...
Does Buying Good Quality Gas Matter?
Gasoline Gasoline is refined from crude oil and can contain impurities and minor inconsistencies. Because of this, it is standard practice for additives to be mixed into gas. This means that one person can fill up their car anywhere and...