Is 89 Gas with ethanol okay for 2006 DTS? Is anyone using it in an 06 DTS non performance? Any problems with anyone who is using or has tried it? Costco has only 89 for $2.62 and 91 premium for $2.91 grrrrrrrrrr No 87 anymore
From your post, it seems like you were using 87. Correct me if I am wrong. If the 89 is E-85.... DO NOT USE IT. If you were using 87 and were happy with it...the 89 would be OK. If you drive kinda briskly... try a couple of tanks of premium. You may be pleasantly surprised at the difference in the way it runs. If you just ease around ... probably won't make any difference.
I put nothing but the highest octane premium I can find in my 2006 Performance Sedan, but to each his own.
I have accidently put lower octane in it a couple of times. It makes a VERY NOTICEABLE difference in the way it performs and hits the fuel mileage about 2 MPG.
10% ethanol is mandated in some states, for better or worse (mostly worse, because it limits consumer choice). The DTS can handle it just fine. More than 10% can harm fuel pumps and hoses.
Use the octane rating specified by your owners manual. No higher and no lower.
I have accidently put lower octane in it a couple of times. It makes a VERY NOTICEABLE difference in the way it performs and hits the fuel mileage about 2 MPG.
Jim from Texas
Jim, part of the reason you notice the big difference is that your vehicle has become "used to" the higher octane. After a few tanks, the car would adjust and the differences would seem like much less. With that said, I also use higher octane than recommended. However, it is required with my performance tune in my Escalade and I do it out of habit in my SLS.
Jim, part of the reason you notice the big difference is that your vehicle has become "used to" the higher octane. After a few tanks, the car would adjust and the differences would seem like much less. With that said, I also use higher octane than recommended. However, it is required with my performance tune in my Escalade and I do it out of habit in my SLS.
I don't really want it to become "used to" the cheap gas. I like the way it runs on premium and a dollor or two per fillup don't mean anything when I know it is running as good as it can.
Surely, if I can afford a new Cadillac, I can afford to put good gas in it.
In my owners manual.. (yes, I know I'm wierd... I actually read it) it states
"Use Premium unleaded gasoline with a posted octane of 91 or higher. You may also use regular unleaded rated at 87 or higher but your acceleration may be reduced and you may notice a slight audible knocking noise commonly referred to as spark knock. If you hear heavy knocking your engine needs service"
I for sure don't want spark knock in "MY" Cadillac.
What the manual "DON'T" say is the mileage will also go down, or at least on my car it does. In that case, the couple of bucks you save on cheap gas will be offset by having to buy "MORE OF IT." So any percieved saving will be more than offset because it is actually USING more gas.
Andy1 in Calgary again. The 89 with up to 10% ethanol is fine. If you have cold icy winters, the ethanol is a perfect gas line de-icer. However do not go over 10% etahanol as it will cause problems with your fuel pump and injectors. 89 should be about 5% and 91 should be about 10% ethanol. Never use E85.
The 05, 06, 07 & 08 DTS can use regular gas with no problems.
The engine has knock sensors, basically low frequency microphones in the valley of the V8 block. These pick up the usual knock noises you hear with bad gas, but much sooner. They tell the engine controller to retard the engine timing so no knock damage is caused. If this happens, you will have slightly reduced power and mileage. The Lux 1,2,3, 05,06, 07 & 08 will run fine on regular. The performance version can use reg, or mid gas but really should use premium.
Hope this helps
Andy1
What I forgot to mention is the quality of the gas you use. There are fuels called Tier 1. These are the best quality gasolines available with the highest levels of injector cleaner/detergent available. If you Google 'Tier1 Gasoline' you
can find suppliers in your area. In Canada we have two...Petro-Canada and Shell. If you use cheap gas, put a bottle of injector cleaner in every 4 -5 tanks
Andy1
--Automobile Magazine, May 2004
I like the way it runs on premium and a dollor or two per fillup don't mean anything when I know it is running as good as it can. 
