Check engine light-left bank lean

Hello all, My 96 check engine light comes on about every 2 months and when I have the codes checked, its always the same- left bank lean. Where do I start to keep this from occurring? Thanks everyone.

Sounds like unmetered Air sneaking in the Intake,thus throwing code.
Rubber,plastic,and gaskets are unstable and will Age with Time.

Suspect:
EGR gasket
Vacuum EGR solenoid
Vacuum hose on EGR feedback sensor.

MCGIVER

Hello all, My 96 check engine light comes on about every 2 months and when I have the codes checked, its always the same- left bank lean. Where do I start to keep this from occurring? Thanks everyone.


Hello Iceheart -

I once had the same code readings as yours, and mine was intermittent as well.

I finally narrowed it down to specific conditions; ie engine load, throttle position, and outside temperature.. I found that it (the CEL) came back mostly while speeding uphill on warm days, with some duration involved too.

The intermittent P0171 & P0174 codes really didn't make sense unless I considered immediate & extreme altitude change, bad fuel in extreme conditions, or bad air flow. Process of elimination (perfect air flow, different fuels, low altitude hills) brought me back to square one.. Code P0171 and sometimes P0174 in the extreme conditions mentioned; shit!

So I brought this problem up with all you folks that I've made friends with over the years.. I got lots of great advice; check this, clean that, use this.. etc. none of those remedies were working.. no biggie.. like you said.. it's only once in awhile and I nearly always have a code reader in the car to help out anyone in need.

So one day I'm bored.. altitude's not it, fuel's not it, and I surely don't have vacuum leaks.. they would show up always. That only leaves air flow... or at least perceived air flow. What's my OBDii telling me, and why? Only one sensor stands between the throttle body and the air inlet.. the MAF Sensor. OK, it's not really specifically related but I may as well have a look.

TORX Security fasteners hold it in place, and I just happen to have a set of security bits. Harbor Freight has a few different sets (http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=93388) of these if you need to buy 'em, mine was $5.00. It's a regular TORX head fastener with a post in the center, forcing you to have a hollowed out TORX bit (security bit they call it) to get it off.

So I go about removing my MAF Sensor, have a good look at it.
CAUTION: The sensor wire should not be touched
The sensor wire has one side facing the air flow, and one side facing the throttle body.. the side that faces the air flow would be directly exposed to the elements that somehow bypassed your air filter, the other side you would expect to find a little bit cleaner.

I was very surprised to find the element side facing the air flow was caked with black sooty shit, and somehow a piece of short/curly hair was wrapped around the element too, yikes.

Cleaned all that up really sparkly with alcohol, blew it dry.. checked the hole where the element seats, checked the inlet tube, cleaned the air box, etc.

No more CEL codes.

Here's some photo's for reference:

http://img217.imageshack.us/img217/3425/maf011b51494yj6.th.jpg (http://img217.imageshack.us/img217/3425/maf011b51494yj6.jpg) http://img442.imageshack.us/img442/8513/maf021b4c8a6am8.th.jpg (http://img442.imageshack.us/img442/8513/maf021b4c8a6am8.jpg) http://img258.imageshack.us/img258/5350/maf031b46c9cny4.th.jpg (http://img258.imageshack.us/img258/5350/maf031b46c9cny4.jpg) http://img406.imageshack.us/img406/9876/mafwires031b3bdcevo4.th.jpg (http://img406.imageshack.us/img406/9876/mafwires031b3bdcevo4.jpg) http://img186.imageshack.us/img186/1904/mafwires021b410c0vh8.th.jpg (http://img186.imageshack.us/img186/1904/mafwires021b410c0vh8.jpg)

Here's the $5 33pc Set I got from Harbor Freight:
http://img15.imageshack.us/img15/5925/933881546719.th.gif (hhttp://img15.imageshack.us/img15/5925/933881546719.gif)

I agree with Steve.

Steve!!!!!!!!!!!!!!! Good to see ya!!!!!!!

1) If you jump on the gas pedal and your car is slow and sluggest,I would suspect MAF too.
2) Random Misfires

It's like trying to run the quarter mile with fingers in nose.

The MAF/IAT sensors are to slow to react for the demand in Power & Performance.

The PCU needs an WOT (Air) signal + TPS to go Fast!
More air going to the Intake (COLDER) = More voltage signal going to PCU.

Just like a Cooktop,oven,stove,or Hot water tank, The Heating elements do go BAD.

As your TC ages your valve seals will leak oil and Egr Gases will blow back and
contaminate your MAF sensor too!

Thats why I put a turnicate on EGR ports on older TC's in the Hood!

.50 cent gasket,or a $500 EGR system repair?

MAF sensors:

AutoZone $100
Salvage yard $25
MAF sensor cleaner $5.00

MCGIVER