I have 1997 2.5TL with 125,000 miles on it. I have noticed, that when cold, my car will crank for an abnormal amount of time before starting (4-5 seconds), this only happen when I run 91 or higher octane fuel. If i switch to 89 or 87, the car starts up right away with no problems every time. I have done a complete tune up, and checked both coolant temp sensors... Has anyone run into this problem with thier 2.5? I would like to fix this minor issue as running 91 would be nice due to the increased performance.. Any input would be apreciated. Thanks!

TLM

 

Do you mean when the engine is cold (first start of the morning) or the temp is cold (below freezing)?

 

Well I use 91 octane all the time. I have a 96 2.5 TL. I don't have the problems you are experiencing. I'm not sure if oil plays a part in cold starts, but I'm using Mobil One 5w-30 synthetic.

 

When I mean "cold", I'm refering to the first start of the day. average temp in my garage being between 50 and 65 degrees... This problem has me stumped...

 

Well whatever it is, it shouldn't have anything to do with using 91 octane gas. It's been cold here...40's in the winter and I haven't had those problems. I've used (Diamond Shamrock) Valero, Shell V power, and Costco gas, all Supreme.