What Could Thid Be ?

[suburban drifter]

i have a problem with my rb25 atm ..when just crusing if i back my foot of the gas slightly thr revs will rise slightly ,say im doing a solid 2900rpm i back off it will go up to 3100 before it goes down...also some times it randomly doesnt wanna go past 4500 rpm as easy as i would like but other times it is sweet as ..any one know what could be the prob ..thanks

[89CAL]

hmmm

thats a bit different, the only thing i can think of is if ur backing off and clutching at the same time you may be clutching just a slight bit before u take ur foot off and its just free reving a bit. If its doing it with no clutch and the car is actually accelerating slightly for a second when u take ur foot off then that is really weird

[suburban drifter]

its only when driving not changing gears or anything like if you whent over a slight bump in the road it would do it when your foot moves

[89CAL]

Ok so for example your driving along in 4th gear (manual im assuming?) at lets say 60km/h and u remove your foot from the accelerator and the revs rise a little before going down?

try driving it hard say for exmple full throttle up to 4-5k rpm then take ur foot off and see if it does it

if it doesnt then i suspect its your aac valve perhaps otherwise...... hmmm

stock ecu?

if so try reseting that, its a weird problem your having and im just suggesting that as a general thing, It may be as easy as that but yeh your problem seems rather weird

[G0DZLR]

does it happen lower in the rev range? whats your idle set at?

i know on a cold day when the auto-choke is active on mine, i can cruise along at about 5-10ks an hour without putting my foot on the accelerator. has been doing it since i had a 100,000 service on it, am guessing its becuase they cleaned the AAC valve and set the idle to 950RPM (instead of 650RPM stock NA)

either way, i find it handy, but dont get your backoff issue. could be to do with something around the throttle control/body/butterfly