i have notice everytime i fill my evo 8 up with a full tank of gas that after i drive off when i am at idle my engine tends to bog up and down (hope that makes sence) just wondering if everyone else gets the same thing as well?

 

Like the rpms jump up and down like from 1000 to say 700 and back and fourth?

 

nope it idols fine, it just bogs. the engine

 

not sure if it would have any effect but are you topping off the tank (continue pumping gas even thought the nozzle has shut off once)?

 

no i stop when it stops, i am just hoping this is not a problem, i took it to a couple shops, and it sucks because it doest happen often, just when i fill it up with gas. i hope this is just normal.

 

bump for some more answers.

 

Do you go to the same gas station all the time? If you do, try going to a different station that sells a different brand of gas. That would at least let you know it's the gas you're putting in. What brand do you currently use?

 

actually i did that, i use both cheveron and shell and thats it.

 

maybe your fuel pump filter is dirty. could try replacing it

 

Hmmm...this is odd. Maybe try putting a bottle of fuel injector cleaner into your next full tank???

 

i sure hope you're using 91+ octane

 

yea i put fuel cleaner, and i use 91 octane, i mean its not really bad, it only happens for like a couple seconds and then its done.

 

This happens to me also. If you had a A/F gauge you would see the ratio's jumping around like crazy, until it settles down after a couple minutes like you said.

I'm assuming that the ecu is readjusting itself. I could be wrong though.
Are you flashed?... I really don't remember if it also did this when my ecu was pre-flashed.

Anyways it doesn't seem to affect anything, and it go's away after a couple minutes so I wouldn't worry about it.

 

The same happens after I fill it up all the way, passes in a couple minutes never happens after that until the next fill

 

nice, alright as long as i am not the only one haha.