I drive a 2003 Mazda 6. In the summer of 2005 and 2007 I was driving my car at an altitude higher than my normal Kansas altitude and experienced vapor lock. (just outside Limon, CO and Cheyenne, WY) The guy who towed my car in 2005 recommended a little diesel (1 cup per tank)to remedy the problem. …

Is your car fuel injected or does it have a carburetor. I don’t believe vapor lock is a problem with fuel injected engines, but you learn something new every day.

Vapor lock was much more common in cars of the 40’s and 50’s and seems so rare today that I wonder if you really experienced vapor lock. Old cars with mechanical fuel pumps only develope about 4-5 lbs of pressure. The high heat in the engine compartment combined with high ambient temperatures coul…

I’ve never heard of this, but my guess was that he was suggesting the diesel fuel as an additive to reduce the octane and effectively enhance the detonation characteristics of the fuel. Lower octane fuels detonate more readily. Interestingly, your husband’s suggestion would have the opposite effect. …

'03 Mazda 6’s were multiport injected.

I doubt it was vapor lock, unless you have a defective fuel injector. The fuel is held at high pressure until injected into the engine, altitude should have no effect (otherwise you’d see lots of cars at the side of the road in high altitude areas). I also recommend against the diesel solution. P…

Vapor lock can and does occur on fuel injected vehicles. A fuel injected system is a closed loop system. That means whatever fuel isn’t used at the engine is returned back to the fuel tank. As this cycle continues, the fuel gets heated at the fuel rail(s) and starts heating up the fuel in the tank.…

My husband suggests also using premium gasoline. No, if anything you need lower octane in the mountains. Note: That does not mean you NEED lower octane, only that your car will get along fine with lower octane.

I’m not a fan of the vapor lock theory. Your car was towed so what were the circumstances and symptoms to cause it to be towed? Quit instantly on highway, stalled in traffic, sputtered and coughed before giving up the ghost, etc.?

I picked 5 “vapor lock” sites at random off the net,all said vapor lock on fuel injected cars “highly unlikely”.

Vapor Lock

Maintenance/Repairs

waterboy July 15, 2009, 10:42pm 7

I seem to recall from other episodes you actually can use a lower octane gas in the mountains. Fill your car up with the minimum octane requirement would be my suggestion. Is premium suggested in your manual? That would tend to go with adding diesel as the net effect is a lowering of octane, I think.

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Vapor Lock

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