Slew of problems after trip thru mountains.

Hi everyone. This is kind of long but we've recently discovered several problems so I better just tell the whole story.

I've had a 2000 Taurus FFV with flexfuel for over two years now and it's never had any engine problems since I've had it, although we once had a code regarding a possible MAF (or MAP? Not sure which we have) problem, but once we reset it the code never came back We currently have between 85000 and 90000 miles on it. The car was made in Chicago, was initially a rental care at O'Hare, and since then has been titled in Minnesota and Wisconsin - basically, it had probably never really been over 2000 feet, or at least wasn't used to it. But I go to college in Arizona and decided to bring my car there this year. My dad and I drove it here but decided to take non-freeways through the Rockies since we come from a flat area and wanted to see the mountains. Our car showed no problems and was getting normal gas mileage until we got to the very top of the continental divide at Monarch Pass, at almost 12000 feet. Right when we shut the car off, there was a boom and smoke was coming from the coolant cap and it was overflowing. Previously it had been somewhat overfilled but I was told not to worry about it. So we let the car cool and replaced the coolant since a lot of it if not all of it escaped, and we did mix the coolant. So we drove down the mountains to the first gas station to check on the coolant level. It was okay by then but suddenly we then had a small leak of transmission fluid. Also, we'd felt underpowered when climbing mountains so we used a higher octane (We hadn't been using the 85-octane stuff they sell up there since the manual says not to, but we did move up from using 87 to 91 or so). We also added a bottle of octane boost. The car performed better then, although our gear shifts were getting rougher, and the shifts between park/drive/reverse were especially sharp. Once we got to our hotel, we added a repairing solution to the transmission fluid, after which the leaks stopped. Also, the next day, shifting became much smoother, although the shifts from 1-2 as well as the shifts between park/drive/reverse still had a slight jolt to them. However, the upper gear shifts had little or no jolt at all anymore. We drove over a few more passes the next day but none were as high as the pass where we had our initial radiator overflow incident. However, while stopped in traffic due to road construction on a mountain road, I noticed some steam coming from the hood, although it soon stopped and didn't recur. Still, we decided to buy a new radiator cap, and noticed it had a plastic pressure regulator/release on it, which our old cap was missing. No radiator problems have occurred, and the transmission was working fine all day. We finally came out of the mountains and hoped the problems were all altitude-related. We came into Phoenix from the north, which means that our altitude had only very recently returned to the 1000 feet that the car is used to. After about 15 minutes of high speed freeway stuff going at least 55, we passed downtown and came into rush hour traffic, and slowed to about 30 or so. Before long at all, the engine started to stall. At first I thought it was a transmission thing since it was jolty, but instead the engine turned off and the check engine light came on solid. We managed to pull off the road and cool it down a bit. We were able to restart it, but now the no-speed transmission shifts, particularly the one from reverse to drive, have become very sharp, but the shifts from 1-2 and those other shifts on the road are not jolty at all. The only code pulled from the check engine light was P0191, although the previously cleared code for the MAF or MAP from months ago never really got solved, but did not seem to recur until our mountain trip. Also, it was 110 degrees in Phoenix this afternoon, and our A/C was on. Also of note is that a couple of weeks ago at an oil change, I was told my fuel filter was getting rusty, although I'm planning to change that coming up here at 90000 miles.

Here are my questions:
- Do you think this is just an altitude problem that will be solved now that I'm in Phoenix at 1000 feet, or does it require a more immediate repair?
- I'm going to retitle the car in Arizona now, and so I'll need to take an emissions test here very soon. How might these problems relate to passing/failing an emissions test?
- Why are the park/reverse/drive transmission shifts so jolty? Is this a separate problem?
- Other comments are of course appreciated.

Thanks for taking the time to read all this. I know it's long but it's complicated too. We had no problems for a good 20000 miles down at 1000 feet in the midwest, but as soon as we take it over the rockies and into the hot desert we have all these problems.

Welcome to the forum!

Your 2000 Taurus should not have any problem adjusting to a change in altitude. I would suspect that you either have an issue with your water pump impeller blade (search this forum for more information on water pump failures and the Taurus), a cracked degas bottle for the cooling system, or a radiator cooling fan that is not working properly. Did you happen to monitor the temperature gauge while driving through the mountains?

Also, your transmission shifting may be due to an over-temperature transmission that has now burned the transmission fluid. Have you checked the condition of the transmission fluid? Is it dark with a strong odor? Even if it's not, it would be in your best interest to service the transmission. There are two schools of thought on whether or not to flush the transmission. I'll let you research the proposed pros and cons of each to make your own educated decision.

Good luck, and I hope your A/C works well in Phoenix! :)

-Rod

Hi Rod, thanks for the response.

The temperature gauge acted very normal, running just under the halfway mark throughout the trip, except when climbing some steep passes, in which case it would be slightly above halfway. It never got near the H.

The transmission fluid is normal. As for the radiator fan, we can hear the fans when they run, and if I understand correctly, there is a secondary fan that kicks in when needed, is that correct? If so, we heard that one running sometimes as well. So far it has run well in Phoenix and it did pass emissions. My dad and I think it may just have been a fluke caused by long mountain drives ending in hot weather, and we're hoping it won't recur on the shorter city trips in Phoenix. Still, I'll ask my dad what he thinks about the water pump impeller, the degas bottle, and the fan.

Why are the park/reverse/drive transmission shifts so jolty?

The most common reason for "jolty" shifts is low transmission fluid pressure caused by a failing transmission oil pump. Have the pump pressure checked.
Other reasons for hard shifts can be the EPC solenoid, clutch bands, accumulator piston or dirty valve body ... have the pump pressure and EPC pressure checked first (they are accessable from the top of the transmission housing).