strange starting problem

[j930]

last summer I had the engine rebuilt. had the correct euro fuel head put back on the car, correct fuel lines etc. had some problems with it running really rich and that was due to improperly tuned car. they got that squared away. recently they found that i had a bad O ring in the fuel head and had that fixed and it was running really well. last weekend we took the car up to Flagstaff for the weekend. Phoenix is about 110 degrees right now and we are at about 1500 feet above seal level. flagstaff is around 8000 feet above sea level and it was about 85 degrees on saturday. started the car on saturday afternoon and it did not jump up in RPM like it normally does. it usually starts off around 1400 RPM and slowly comes down to about 950. this time it started around 700 and kind of stumbled up a bit. when i gave it gas it seemed like it was flooded, like it was just chugging along. i shut her down and restarted to the same thing. i gave it some gas and it cleared itself up. it was a little groggy and unresponsive. the next morning it started right up and ran perfect.

a few years ago i had a plane that i flew around to build hours. I remember when i was at higher elevations it was a slightly different starting procedure as the air density was greatly diminished. could that be happening? would the car need to be tuned for different altitudes? i know in the newer cars its all computerized. any thoughts are greatly appreciated.

84 930S. euro fuel head all stock. K27 turbo larger intercooler no other mods.

Maybe its just the way it is?