2015 Cadillac Escalade 6.2l 4wd 8 speed
Okay i want to make this as short as i can. I own a 2015 Escalade with the 8 speed transmission. I bought the vehicle in Dec 2019 in Fresno California while visiting my parents for Christmas, I live in Idaho falls Idaho (5500ft above sea level) when i purchased the vehicle it ran okay for a minute then started to misfire and shutter. I changed the spark plugs and wires because i had to leave to idaho the next day, at that time i got a cylinder 7 misfire code then a random flashing check engine code also. I left the next day to Idaho. The car did the misfire and would shutter under low RPM and up hills. Well i ran sea foam every fill up that day and when i got to Reno Nevada it started running perfectly! Then on to Idaho and the car was amazing no check engine no shuttering just a rough idle which i here is standard in an overpriced vehicle Anyways fast forward a year and my wife and i take a job in Vacaville California. On our way there in Nevada at well above 5000 ft it misfired badly! We got to California and i got a cylinder 2 misfire. Now i just decided to go ahead and do all the injectors myself as i know how to. I know those injectors suck so i got the new injectors that were the same part number, keep in mind i know they have issues but i got all new 8 for a good deal and figured ill give it a shot. Install went great and no issues. Except....the car still now throws only a random misfire and the dang thing is popping bad in california still. So i found the TSB on the 8 speed transmission that has a class action suite against it and every symptom it had made me convinced it was the torque converter ”shuddering” I took it to the transmission shop and that transmission is actually in great shape so i did the mobile one oil change still as recommended. Still while in California i get no power below 2000 rpm and under light acceleration. With terrible popping at the exhaust. Okay I’m sorry this is long. So what did i do next, i changed the MAP Sensor and the Mass air flow sensor. Still same problem at sea level. Well Christmas 2020 happens and we take off to Idaho Falls Idaho and as soon as i hit Donner pass at 3000 feet the vehicle wakes up and i have all the power no misfire and no shudder and all the power the 6.2l can give me!! After 2 days in Idaho Falls, ID the check engine light goes out and the week and 2 days we are there for Christmas with our other family I had my Escalade back! (With the semi rough idle still) Well today we headed home at 4am and as soon as i hit 2000 ft elevation and down to vacaville CA all the same symptoms came back. The bad popping and loss of power unless i manually shift and keep RMS’s above 2500. I am at a loss and need help can anyone help me on this or had this happen? I probably missed details on this but i know them all any response and help will be greatly appreciated we truly love this car and i am willing to pay to fix what i need to.