My problem is when my tank of fuel is full - my throttle feels really sluggish and slow. But when the tank is almost empty throttle feels VERY sensitive (like it should be from the factory, I guess). And it is not because of the additional fuel weight, if a big friend of mine sits in my car when the tank is almost empty - throttle is still very sensitive

My only guess is fuel pump, as I cleaned it several times (here we have very dirty gasoline sometimes), but I can't imagine why

Maybe it is somehow connected with the self-learning ecu?

 

Maybe my EVAP system is dirty or something is wrong with it. Has anybody dealt with it?

 

Hmm, I've never heard of this problem before, but I think you're onto the same line of thinking I'd be pursuing here with the EVAP system. Maybe you should see if you can identify where the symptom kicks in relative to how full the tank is when refueling. For instance, if you stop filling at 7/8 of a tank, does it still occur? When it does occur, how much fuel do you need to go through before it resumes normal operation? Or is it more a function of time before it resumes normal operation again? Is it 100% consistent, or does it only occur intermittently? If you refill all the way, but then just let the car sit for a day or so (to let the EVAP stabilize/settle in case it's only marginally working), does it still do it?

 

the problem is that it is not 100% consistent, so I can have laggy throttle pedal when the tank is almost empty, but most of the time it happens when the tank is almost full or at 3/4, 2/3... there is some connection, I'm sure!

maybe I should do this ITB: http://x.infinitihelp.com/forum/loca...tid=77&id=1113 - VENT CONTROL VALVE REPLACEMENT ?

 

you have an 80 gallon tank instead of a 20 gallon

 

Thank you for the comment Zomorg3. But to be serious, you have to understand that their our several causes that it might seem sluggish when you get gas. You might need to change gas and go to another station because they might have bad gas. You might need to give your engine a good fuel system cleaning because their is dirt that is getting to the fuel lines and pumps. Check all your injectors and make sure they our all firing at their set capacity. You might have lots of carbon buildup either at the heads or in the throttle body that is causing issues at certain times. In your situation i would go to another station first, after that try like Seafoam and do your fuel. Then i would start looking at the motor, start eliminating possible causes.

 

Haha you know I was joking. Go to autozone or w.e and get Lucas injector cleaners. Hopefully you have been running 91 octane or higher. If u have a place that will check to see if you are throwing any codes that would be quite helpful. Possibly to gass gauge I know my parents QX56 was recalled for that

 

Looks like OP is in Ukraine...

Using better fuel... seems to be the first thing I'd start with as well....

 

Might be in your head.

Other possibility is heat soak from parking at the gas station.