Only Premium gas in 1998 Cadillac Deville


New LVC Member
Aug 6, 2009
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Hi, I'm looking to buy a car and a nice 1998 Cadillac Deville caught my attention, however, I have never owned a cadillac. Is it true that in the 98 series they only take premium gas? Thanks.
No! You can run regular gas. The engine will adjust to accept regular. I used regular in my '94 Eldorado with a Northstar engine and now I'm running regular in my 2005 STS. Premium is recommended for both, but regular will do just fine.
Its 20 cents more per gallon for premium, cmon. Yes it has knock sensors which can compensate for regular, though it does so by retarding timing. Which can often result in lower mpg, higher emmisions and less power. Even then many still knock. In addition very often the oil consumption on northstars is due to carbon build up this only adds to that. Buying cleaners then to compensate more often also negates the .20 cost savings.
i tried reg gas and it drives more sluggish and the miles per gallon or Kilo per liter is less then when using supreme or high grade gas. well my ride anyways

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