good idle, running bad...wtf

[HKsilvia]

3 days of searched plus 3 hrs sleep per night due to work doesnt seems to help so im begging for some help.

SR engine, been swapped for year already and doesnt seems to have any problem. recently it starts giving me symptoms, last months while i was driving on freeway it chocked on me once. just like the car is running out of fuel for 1 split second. (i still have half tank) at first i thought the road was bumpy and the coilover causing some wheelhoppin so i didnt pay much attention. however, this "chocking" symptoms starts appearing more and more frequent, at first it only happens on freeway, but then it starts happening on low speed local driving. i decided it is not safe the drive it around so i leave it for 2 nights. 2 days after, i started my car, the car cant idle anymore, i rev the engine and the car barely response my right foot.

so i took it to the shop, their answer is im having a vacuum leak and charge me for $45, i got my car back the same day and its run fine, idle ok, no "chockin" issue until the next day, which is today, this shit came back again!!! even though idle is still fine, but "freeway chockin" definitely driving me nuts.

so with all the common sense and all the searched i had come over so far i would say it is something with the fueling system, especially fuel pump and fuel filter (lets hope the fuel lines are ok). however there is only one thing in my mind... if im having problem with fuel system (hopefully) why my idle can be so stable, shouldnt it be rough? i even rev the engine and it didnt shows any bogging/hesitating.

am i in the right direction? or is it possibly something else? im planning on buying a walbro 255 as replacment, but how about fuel filter? are all SR engine using the same filter as Z32 filter?? i dont want to spend money on the wrong stuff.

thx for reading, any help is appreciated.

[turboeic]

My car did somewhat the same thing but its a KA. But try cleaning the MAF.

[20 til 3]

it's your MAF. You spelled it out at the subject line.

[HKsilvia]

sry for not mentioning ... i did clean my MAF...like last week, and i did test drive the car right after... same problem
btw i thought MAF problem in most case will affect the idle, isnt it?

my idle is perfectly smooth and never stall........yet
at least thas what i have seen from all the other threads so far...

thanks for the info tho... i will take off my intake and try cleaning it. since i just spray it withut taking it off last time.

[slider2828]

It could be a broken mafs as well. There was a thread with a movie on how to fix a mafs and check whether if it is broken. Mafs is a wire lead and solder points and the solder points can get loose when pressure is applied or going over a bump at speeds like a railroad track or something. Look for that thread, otherwise, change your oil filter and maybe a fuel but first the easy check is to see whether if your mafs is broken

[20 til 3]

Originally Posted by HKsilvia

sry for not mentioning ... i did clean my MAF...like last week, and i did test drive the car right after... same problem
btw i thought MAF problem in most case will affect the idle, isnt it?

my idle is perfectly smooth and never stall........yet
at least thas what i have seen from all the other threads so far...

thanks for the info tho... i will take off my intake and try cleaning it. since i just spray it withut taking it off last time.

your MAF doesn't kick in until around 2000 RPM. It will idle just fine if your MAF is disconnected.

Oh and to answer your question, yes you can get a Z32 fuel filter, which is recommend, as it is bigger then a stock SR fuel filter. I wish I could help you out more, but with the symptoms your giving me, I still lean towards your MAF.

[HKsilvia]

ic ...i will do that thanks all
btw i found it
http://robfleming.net/mafrepair.html

by what that person said, MAFS in unservicable and it is very hard for unexperience to repair...if im gonna buy one, will the dealer sell those? MAFS for SR?

[pbcstylez]

clean the MAF like the link you found, than clean out your IACV, this should fix your problem. im almost guaranteed.

I had similar if not identical issues, i just hosed my MAF down with Electrowash inside the MAF (board included) let it dry real good and reconnected and wallah!

gluck