Guys am having this problem driving me crazy....when i drive the car while the engine temp. Is cold its driving perfectly but once its reaches normal temp i face huge engine power loss its like am driving the car with one cylinder missing the car feels heavy the throttle feels not responsive and stupid and its like on limp mode but without the speed and trans limits ... no CEL light nothing .. i replaced both throttle bodies and maf sensor still the same...took the car to the dealer stealer for major service rlaced spark plugs and they checked compresion and its fine .. the only mod i have is berks HFC and am sure the driver side one died is it related to it.?
Ive done alot of research abt this problem but it made more confused as it may be related to many things like bad temp sensor or bad cam shaft or cranckshaft sensor or O2 sensor i dont know where to start !!!
One more thing when i put the gear into drive from P or N the car shakes and the rpm drops for a second then goes back normal but then it stays @500 or 450 which is very low when i compare it to my frineds cars...
Sorry for this long story but the problem is making soooo fraustaed and makes me hate me car
Your help guys would be very appreciated
Mine 2008 sedan journey

 

you should check for leaks on your exhaust, then it could be your oxygen sensor or your HFC is clogged and you will have to replace one side or both. it could be that your car needs to get computer reset that includes throttle body, accelerator reset. your car has fuel and air learning computer so it can adjust to certain amount of mods before getting your computer reflashed and tuned on dyno. try these first. take your time don't rush. check out gshack.org for the manual.

 

Resurrecting an old thread here, but I am facing this exact same issue. How was this issue solved?

My engine runs great for about 10 minutes after start-up and once fully warm it suffers a huge power loss. Once warm it no longer idles at 650 but between 1200 and 1800 RPMs and surges a bit. When I step on the gas it feels like it's a cylinder down and runs very rich as well.

Important note: I just had the Osiris tune last week. Since the dyno-tune I have put ART Pipes on the car. The Up-Rev tune was done with Berk HFCs (because the fools at the performance shop took off the brand new ARTs I put on myself and replaced them with the used Berks they found in my trunk... long story for another day. The shop promised me a retune with the ART Pipes to get me to pay the bill and have been ducking me since).

 

Sounds like a bad tune. Sounds like a timing issue

 

Exhaust leak will kill your o2 sensors. This will result in poor fuel economy and poor part throttle acceleration.

However, for full throttle, cars don't use o2 sensor feedback. They go into power enrichment mode and it's all based on tables. So a bad o2 wouldn't affect full throttle.

 

I would avoid that shop from here on out. If they took off ART pipes and put on hfcs, then they obviously aren't very knowledgeable about the platform, which means they are probably new to uprev. Are they an authorized tuner on the uprev website? If not, take it somewhere else