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Discussion Starter · #1 ·
So I am pretty certain i'm having an issue with vapor locking with my car.

Last summer, usually only when I had the A/C on and was in high elevation (7-8k or more feet) my car would vapor lock pretty bad. It wouldn't want to accelerate unless I mashed the gas and kept the RPM's up. I didn't really have the problem around town.

I figured that the problem would have been reduced with all the work i've done to the car in the last year. I guess I was wrong!

Today I was out running errands around town, half highway half city driving. It is about 95-97 out here in Denver. I had the A/C on and I noticed that on my way home from Downtown Denver that when I would take off it would start to go, bog down pretty bad (didn't feel like it was going to stall, just no power) then it would take off after about 5 seconds. I tried letting pressure out of the gas cap, didn't do much. It was the only thing I could think of though for a vapor lock issue.

So my question is, does anyone have anything they could think of that would cause this. I did some research and I saw that one website said it could be from the fuel pump getting hot? I know that all my maintenance is more then up to date, and the fuel pump was replaced last year. I called my Saab indie and they are stumped.

It also does this with the a/c off. Hmmm any ideas?
 

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How do you know it's vapor lock? That usually only happens on a hot start. If it happened while driving, there should be a 'lean running' code stored; same for the fuel pump. If you are getting vapor lock, fiddling with the gas cap won't do anything.
If it really is a fuel problem, you're going to have to drive around with a fuel pressure gauge so you can see what happens when it stutters.
Failing Crankshaft Position Sensors can give you those symptoms when hot.
 

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Discussion Starter · #3 ·
I'm not having any hot start problems, just the shuttering when it gets very hot out.;oops:

The fuel pump was replaced at the dealer about a year and a half ago. Would this problem throw a cel? None have been on. Is it something that a specialist with a code reader?
 

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Discussion Starter · #4 ·
Well. The fuel pump was replaced a year and a half ago at the dealership. I guess my bet is going to be on the crank position sensor. I've replaced all the filters in the car, and flushed everything at least twice. I was hoping the open air intake would have helped it but it hasn't.

Would any of the lean codes through the CEL? Is this something the specialist could plug in ( I know its not OBD2 )
 

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Vapour lock is extremely rare with modern high pressure fuel injection systems. Extremely rare. Water contamination is much more common. You don't have those symptoms either.

Fuel filter replaced on schedule? These last a long time but if they start clogging up you will notice.
 
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