Intermittant Off Boost Hesitation

[Spook's_Skyline]

s1 R33 with 150000ks on the clock

original coils and afm, powerfc and 200rwkw

iridium sparkplugs put in around 70000ks

bosch o2 sensor put in 6 months ago, works fine

12month old walbro fuel pump which hasnt given any trouble yet either

no previous issues, until last week, noticed slight hesitation/miss cruising on highway around 2500/3000rpm

back driving around town it occasionly shows up, only when car is warm and so far only at cruising throttle, never when getting some stick

the other nite driving home from work, was large hesitation, car felt like it was going to stall at 60km in 4th

then just stopped and was able to drive home normally

later that nite, car started, drove into street and then hesitated, died completely

would start, and just stall straight away

this happened for about 5 minutes, before i could get the car started, got the car reving and got home

left it out over nite

started fine the next morning, drove it to my mechanic, where it refused to play up at all

got a diagnostics guy out, he coudlnt find anything wrong

mechanic seems to think its afm playing up?

there doesnt seem to be anyway to make it play up, still goes good when booted, and happily cruises along 99% of the time as well

anything i can look out for on the pfc hc to try and determine whats happening?

thinking maybe fuel filter?

anything else it mite be that i can get investigated?

[Spook's_Skyline]

car is now regularly stopping

so ill just take it to my mechanic

driving along, u can feel the car trying to stall

once it does stall, i start the car up and dies straight away

do this for a few minutes and then it starts and goes fine again

maybe the fuel pump is had it

[zebra]

Yes sounds like AFM.

Pull it off and clean it with electrical contact cleaner which can be bought from places like dick smith.

Does it blow black smoke every where when its not running right?

My car did the same thing but only when I blew a cooler pipe off so the AFM was bypassed.

Also check your coils but it shouldnt stall completly if it was coils unless all of them are stuffed.

Check the Air Flow voltage on the PFC HC when its playing up....should be about 1.4-1.5v at idle

Andrew

Edited June 30, 2007 by zebra

[Spook's_Skyline]

was afm

graphing the afm you could see a vertical drop in teh graph whenever it was playing up

replaced with z32 afm