Vid of bad idle, lean???

[ned032002]

I made short vid of my car running at idle and w/ a AF gauge I see that she is running really lean then she goes up when the ECU tries to correct the idle but drops back down after a second or so.

http://s28.photobucket.com/albums/c2...t=MVI_0254.flv

I know that this is just another bad idle thread but w/ the video, what would make me run lean that bad?

Also when I get to about 5,000 RPMs the car begins to buck real bad as if I'm hitting fuel cut over and over again. Any ideas?

Also the noise you hear in the video is not bad lifter tick it's actually my license plate holder on the front rattling.

[tfoti]

Vaccuum leak, which will be a boost leak as well. Get a boost leak tester to see where its leaking from.

[Thor06]

First off, I dont think that narrow band AF guage is worth its weight in shit. Honestly, I have nothing to help you except that I dont think you ought to be trying to diagnose your car based on that guage.

[ned032002]

Originally Posted by Thor06

First off, I dont think that narrow band AF guage is worth its weight in shit. Honestly, I have nothing to help you except that I dont think you ought to be trying to diagnose your car based on that guage.

Obviously in the video you can see that there is an issue w/ fuel as well as a possible boost leak. And I'm not trying to diagnose the car by that gauge, I was asking what would cause me to be so lean? Could a bad fuel filter do this? and how do I get my hands on a boost leak tester?

Has anyone tried this kind of Boost leak tester?
http://www.vfaq.com/mods/ICtester.html

[SilvrEclipse]

You have to build the boost leak tester. When I have logged my NB sensor it always seemed to jump between .2-.8v

[gthompson97]

Just because that gauge says your lean, doesn't mean that there's something wrong with the car. Those narrowband gauges will jump all over the place while driving, the only real thing they're good for is to give your passengers a little light show. A bad fuel filter could cause the car to run rough like you're explaining, but there could also be many other factors along with it. When was the last time you did a full tune-up?

Do the boost leak test and let us know what the results are.

[Thor06]

Its not a true reading Ned, its the ECU's guess as to whats going on. Also, when the car isnt under load it doesnt require the same AFR's as it does under WOT. This is the same reason why you dont build boost when free revving and why you dont burn as much gas idling at say 2.5k rpms as you would cruising at 2.5k rpms. If you are talking about the RPM cycling that happens at cold idle to DSMs (which is what it sounded like was happening in the video) its not an AFR problem, its I think a IAC or maybe a TPS problem.

[SilvrEclipse]

Originally Posted by Thor06

Its not a true reading Ned, its the ECU's guess as to whats going on.

Im pretty sure that reading is coming from the o2 sensor sensor, not the ecu guessing. Unless your talking about the boost gauge

[Thor06]

http://www.automotiveforums.com/vbul...ght=narrowband

If you read that link you can see where I stopped reading . Either way, read that thread and search narrowband (which is what Ned has we think) and you'll see what I'm talking about.

[david-b]

Still... the gauge is way off. No matter what the "accurate" reading is, the A/F gauge should be showing a more fuller sweep. Mine goes top to bottom and back again when warmed up. It's never low like that.