Gasosline brand differences?

My check engine light comes on intermittently depending on which gasoline brand I use. With Shell, it usually doesn’t happen, but with other brands, particularly the grocery store brands, it does and stays on until I refill with Shell. My partner says all gasoline comes from the same pipeline and there’s no difference. My mechanic says otherwise, and there’s no computer readout that identifies a problem. My 2001 Jetta wagaon has 97000 miles, and this has been going on for about 3 months.

There is no difference with the base fuel, but there is a difference with the additive package. Each of the major brands have their own additive package, but a lot of ‘store’ brand or independant stations usually buy what is left over, and mix the different brands together. Maybe your car is sensitive to this, and I’d advise you to stick with what works, Shell. Also, have you tried Amoco, BP, Citgo, Texaco, Hess, Exxon/Mobil, Phillips 66, or any of the other major brands?

Assuming the fuel matches the octane requirements of your car, there should not be a difference.

So let’s hear about those computer readouts. If the only problem is the CEL coming on after using brand X the then the codes are related to the problem.

Frankly I doubt if the gasoline is the problem or even related. That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.

last year here in the uk ,we had loads of reported problems with cheap supermarket caused thousands of cars to breakdown,they all required new oxygen sensors.thats why i always use a descent name brand fuel,such as texaco,shell,b.p,etc… because they use additives,to keep the fuel injectors clean,and it only costs a few pence more per gallon.i also use high octane,which is 97 octane in the uk,which prevents pinking(pinging as you guys say!)so that also prevents engine damage,for only a few pence it cost me ?5.45 a gallon, thats $9.80 in your money!!you guys are so lucky with your cheap petrol!!