Weird Hesistation/splutters Wen Driving..

[bumble_bee]

hey, i ve got a r33 rb25det..

for lik a week now..ive bein noticing weird hesitation..well more like little missfires.. or splutters would be the word im looking for..

from i believe it only wen de-acceleration..

lik ive back off the throttle to like change gear for example..or just back off...

but wen i go to accelerate again..it does it..so its not a boost thing..

and im not acclerating hard or full throttle..like 10-20& throttle...so like just from daily driving...so im not evan close to hitting boost..

my mates reckon it sounds like a vac leak..

wen driving..the only thing i can describe it just feel lik ive dropped in power for lik a spilt second...u can feel it in the accelerator pedal...and u can hear here abit..

well the splutters..

but not all the time does it do it...its so weird..

ive changed new plugs and there gap to 0.8m..

clean afm with afm cleaner..

clean iacv wit carby cleaner..

and ive check for vac leak..cant here anything..

did check all silicone hose..just incase and there hose clamps...

and they seem all good...

any ideas?

my engine mods are

walbro fuel pump,fmic,pod,splitfires,apexi afc neo, hks catback exhuast,hypergear atr28 g2 turbo,hdi type-d ebc

[The Dan]

could be injectors, could be the tune in the AFC but if it's only been for a week that's not likely. I would suggest having the injectors ultrasonically cleaned. Also make sure your TPS doesn't have a dead spot at that throttle position. Voltage check it while slowly bringing on the throttle.

[33gtst]

afm? Mine did a similar thing, had a complete cut at low rpm and light throttle. Replaced afm, all gone!

[hypergear]

This happened long time ago to our test car. Its from the turbo's dose. Happens when turbo throws air out to wards the AFM and then suck it back in. After I put the AFM in side cooler piping this issue was solved.

[Schoer_gtst]

edit should read entire posts before replying

Edited March 25, 2009 by Schoer_gtst

[bumble_bee]

hey 33gtst,,

wat do u mean by low and light throttle cut??wat did it feel like??can u explain it abit more??

or did u have any other noticable issues that appeared too?

thanks

[mook1]

sounds electrical.. loose connection somewhere.

bov issues, is it stock?

[Tangles]

I just had this similar issue, after a tune last week.

last night replaced the spark plugs with new ngk bcpr6e .8mm plugs

had the battery disconnected during the job, reset and its all fine now.

[bumble_bee]

na, its got a atmo bov..

but its set on hard..

so it completely flutters..

but the problem..is on off..

like it will do it lik 1 out 3 days..

sometimes 4 days..

its freakin annoying!

[paulr33]

my recommendations

fit the std bov in plumb back mode

replace with a known working AFM

the likely suspect is your BOV, its probably venting vacuum pressure and its enough to annoy the AFM

which makes the car stutter and hesisate

[bumble_bee]

well...i think ive faulted my problem..

i noticed wen on the freeway the other night..

i notice on my afc..that a/f% was on about 10%..then all of a sudden it would just randomly drop to lil 7/8%

nad i could feel the hesitation from this...it did it a couple of times..then it just went away.. ?????

but my throttle was in the same position...just cruisin..no boost or anything..

so what i can gather from this this its the afm cutting out..

i just open the silicone top black cover on the top off afm.

noticed the 3 wires that connect to the main board looked fine..

but i still did re-solder them...

and i gave the board a good clean of electrical contact cleaner...

hopfully shes all good now

[Jet 20]

Mine has the same problem, only happens when just opening the throttle off idle or 0%.

I'm running a microtech ecu with no afm.

the cause of mine is the throttle position sensor, i can watch it on the laptop and when the throttle is closed the throttle percentage creeps all over the place until i touch the throttle.

like 3lit3 32 says, "dead spot in the tps"

but at $208 i have not ordered a new one yet.

[BUKLUP]

are you using 98fuel? what fuel is the car tuned to if tuned at all?

[bumble_bee]

well my problem seems all gone now..

bein 3 days now..

and havent had a problem since...