5300ft above sea level, car runs like crap.

haha no help, but 4,000+ft is just normal to me?..

Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

See http://www.troublecodes.net/Ford/





IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.



89 through 95 cars have a working Check Engine light. Watch it instead of a test lamp.



Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see http://www.midwayautosupply.com/pc-7208-90-equus-digital-ford-code-reader-3145.aspx – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

You are right about the MAP sensor acting as a baro during crank-before-start. Where i think you may be missing is that there is just less air up there. Thats the nature of high altitude.

Not only does the altitude affect air density...it will also affect your ignition system (spark plugs) At 5000+ ft. you can alleviate the issue to some degree by running a plug that is at least one step hotter. remember though if you run the vehicle a lower alts...you can run into detonation/preignition.

Air density decreases by roughly 3% per 1000ft above sea level. This means at 5300ft you've lost 16% air density. Nevermind the losses in the ignition system...you've lost a significant amount of power just from the air density.

Slap a turbo on that SOB...they create their own atmosphere!

sorry, not to hijack but i don't really want to start a new thread...
but i've never really thought about altitude affecting performance much before this, and i'd like to know more...
i only drive at 4000+ ft around here, so is that why i can run 18* timing? i've never found any reason why my car can take so much advance... also, how much power loss comes from high altitude?

This is why the fastest cars in the country run at as close to sea level as possible.

It is not a coincidence

Good Luck with your adjustments.