Horrile idle but car runs fine?

[JCell]

So two days ago i decided to run blow-trough-maf. the car has been running great until today

im leaving publix and merge into traffic, no problems, i go into boost to catch the light, make it, and drive normally after that.

then, at the next ight, the car wont idle, it tries to die and eventually does. i crank it up and the problem is still there. but when i get the car rolling it runs ok, no hesitation, no hiccups, next light it dies

i get home and let the car cool off. couple of hours pass and i try to start it up, dies almost immediately, the only way to keep it going is by reving it up.

my first thought was the maf. so i switched it and put my maf in my roommates n.a. p5. His car runs fine.

what else could it be? the car hasnt trown a cel yet

Thanks

 

[speed1016]

See and I thought I was the only one. This happened to me yesterday. I cleared my o2 sensor light and waited about 5 minutes and the car ran fine. It almost seemed to not responed to fuel at first. But the car car great. I have no clue! Sorry

 

[JCell]

im in the same boat, it has to be a sensor since it runs good while driving, air/fuel ratio is normal at wot and crusing

but during idle it goes up to 16.5-17 and off the screen.

 

[speed1016]

Same here. Im really stumped since there is no CEL for anything other my o2 sensor. (catless and to cold to fix right now)

 

[StealthWyvern]

um... IAC....

Edit: Just looked up the cost on one of those and wow... I hope thats a typo...

Idle Air Control Valve Duralast / Idle Air Control Valve

for a 2003 Mazda Protege

About this product:
Part Number: AC4075
Weight: 0.695 lbs.

Pricing:
$499.99


Edit #2: Just called autozone or ricezone if you will and that is indeed the price so junk yard for you guys!

 

[speed1016]

Where is this located? Im looking and I dont see anything like that. Do you have the OEM partnumber? And if this was bad would it not do it all the time. My car ran fine today.

 

[StealthWyvern]

Where is this located? Im looking and I dont see anything like that. Do you have the OEM partnumber? And if this was bad would it not do it all the time. My car ran fine today.

not really and I'm not sure. I know the one on my truck(Iknow different car but same concept) went bad but it still ran fine majority of the times.

 

[magnumP5]

Vacuum leak. If your idle AFRs are upwards of 16:1 and higher than something isn't right. You haven't thrown a CEL yet?

 

[JCell]

nope, just cranked it up to put in the garage... looking for a leak now

 

[speed1016]

My vac is fine replaced the hoses about 2 months ago with the hose kit from corksport. And this happened yesterday and today its fine. Ill go over everything again this weekend. I only drive it on weekends anyway

 

[fillyspeed]

i still think you got a leak....mine did that as well. or maybe your BOV needs adjusting if it can be adjusted.

mine used washers....i had 1 in and it idled like crap and would stall, i put them all in and the car ran perfecto until my brother destroyed the car(five-0)

 

[speed1016]

hmm, I guess Im going to have to set a side a few hours this weekend and go over everything

 

[StealthWyvern]

Do you have a boost/vac gauge? If so whats your vac at idle?

Vacuum leak. If your idle AFRs are upwards of 16:1 and higher than something isn't right. You haven't thrown a CEL yet?

Yeah it could be a vac leak. Didn't think about that. However when I had a wide open vac line on my car It didnt idle funny.(was -16 with AC off and now its around -21 AC off). My car did want to stumble at lights at times but not a every time I come to a stop deal.

 

[speed1016]

MIne doesnt do it at every light it was once one day for about 10 minutes. But my vac at idol is around -21 -22.

 

[JCell]

Do you have a boost/vac gauge? If so whats your vac at idle?



Yeah it could be a vac leak. Didn't think about that. However when I had a wide open vac line on my car It didnt idle funny.(was -16 with AC off and now its around -21 AC off). My car did want to stumble at lights at times but not a every time I come to a stop deal.

vac is normal between 22 and 15, but since i have to keep giving it gas so it can idle i cant rely on that.


vac leak makes sense.... i just cat find it

 

[JCell]

o, and i have the new hks non adjustable bov

 

[magnumP5]

Yeah it could be a vac leak. Didn't think about that. However when I had a wide open vac line on my car It didnt idle funny.(was -16 with AC off and now its around -21 AC off). My car did want to stumble at lights at times but not a every time I come to a stop deal.

+1 My vacuum at idle would be perfect most the time but once about every minute or two the car would stumble. It did this enough to throw a lean CEL and occasionally the car would stall. All this because my catch can had a small leak. It wasn't visible on my boost gauge.

 

[speed1016]

Ill check that also.

 

[StealthWyvern]

https://www.ebay.com (commissions earned)

 

[lyserjic]

jCell,

See my post here: http://www.mazdas247.com/forum/showpost.php?p=4331183&postcount=6

Hope it helps.

-Lyserjic
SpicyO #1291