Premium unleaded only

I recently bought a used 2001 Mitsubishi Eclipse. There is a sticker under the gas flap that says “premium unleaded only”. It definitely looks like it was poorly applied, which lead a friend of mine to wonder whether there was some aftermarket microchip installed, which is extremely possible, as there is an aftermarket air intake and muffler on the vehicle. I would prefer not to spend money I don’t have to on premium gas. Anyone have any ideas as to whether I need premium gas?

If you don’t have an owners manual, call a Mitsubishi dealer and ask them. And barring any real engine modification, the type of fuel required shouldn’t be any different than stock.

Spark Knock or Detonation (they are two different things) are both easy to detect just by listening for it…If you can not detect any “ping” or “knock” then whatever octane fuel you are using is okay. Before you can damage your engine you will get a distinct audible warning. Spark Knock is most likely to occur when the engine is under a heavy load at lower RPM…So try 3rd gear, 1800 rpm and floor it…If it’s going to knock, it will do it then…

It is my personal opinion that few engines actually need premium fuel. Todays “premium” is only 92 octane…That’s a joke…Dropping down to 87 octane MIGHT cause a little ping in sensitive engines, but even then, it won’t be at destructive levels. Many here will disagree, but few have ever heard an engine “ping”…Please let us know YOUR observations…

2,351 cc 2.4 liters 4 in-line front engine with 86.5 mm bore, 100 mm stroke, 9 compression ratio, overhead cam and four valves per cylinder

Unleaded fuel

Fuel economy EPA highway (l/100km): 7.6

Multi-point injection fuel system

Main 62 liter unleaded fuel tank

Power: SAE and 100 kW , 147 HP @ 5,500 rpm; 158 ft lb , 214 Nm @ 4,000 rpm

You don’t say what engine,I find at least 1 of the v6’s is listed as preminum required.

Gasoline is a powerful solvent, so a sticker that’s on the gas flap where it’s constantly exposed to gas fumes and occasionally splashed with gas probably isn’t going to look to good after 9 years.

If it is the turbo version then yes “required”. You need to specify which engine you have.

The 3.0L V6 model required premium, the 2.4L I4 does not. Also if this car is a 2001. Chances are it wouldn’t have a “chip” per se. Modifcations to the ECU would’ve more than likely been done with a hand held tuner via the OBD-II port.

.If you can not detect any “ping” or “knock” then whatever octane fuel you are using is okay.

All that means is the anti-knock sensor is working. Doesn’t mean it’s the correct fuel. If car DOES require higher octane then using regular…the anti-knock sensor will back off the timing…giving less performance and lower gas mileage.