Ok, for the first time the "check engine" light has come on. It only took 140K miles to do it!! I had Auto Zone check the code and he told me the engine is running lean, not getting enough gas. So, I came here and did a search on engines running lean. I just want to be sure I am not missing anything.

Details:

1997 4.6 L with 140K miles.
Substaintal exhaust leak at my drivers side exhaust manifold.

Potential Problems:

1) Exhaust leak -Ordered JBA shorty headers to replace stock manifolds

2) Replace O2 sensors - I bought Boshs to replace (They need to be replaced anyhow)

3) Dirty/clogged injectors - Bought some Chevron Tech. Fuel Treatment - if not treatable replace

4) Dirty Fuel filter

5) Bad fuel pump


Did I miss anything?

Thanks in advance.


Dave

 

if u wanna test if fuel pump is bad. run it to about 4,000 RPM in neutral and see if it skips any. a bad MAF or a cracked PCV valve will give u a lean code or a bad 02 sensor will also. along with and fuel accessory.

 

Just because the drone at AZ said it was "running lean", doesn't mean that it is.

Most of them haven't a clue on how to interpret the actual codes.

Post the exact codes , then we can help you diagnose it.

A good example is the P0171 and/or P0174 code(s) which are described as "fuel/air ratio is too lean". However, anyone with a clue will read the whole description of "(DTCs) P0171 bank 1 (Cylinder 1) and DTC P0174 bank 2 indicate the fuel/air ratio is too lean. The fuel trim system is at the rich correction limit." This means exactly the opposite of what might be assumed. It, in fact, means the the onboard sensors think it is too lean, so it has maxed out the fuel trim to the rich side.

Possible causes include O2 or MAF sensor faults which are causing skewed readings or the ever-popular vacuum leak that allows un-metered air into the system resulting in a true "lean" condtion.

A word of advice: Don't take troubleshooting advice from the guy at AZ unless he has the qualifications to back it up such as he/she is a moonlighting or retired mechanic.

rant off---

Steve

 

Right on!
The codes are always refering the the computer action and not always the engine's hardware.
Lean means the computer's fuel tables have been "LEANED" , not the fuel TO the engine.

 

bosch o2's suck and last only 2-3 months. buy an oem one, the last one you got 140k outta

Oh yeah, and platinum +4's are the dumbest idea ever. electricity travels to the path of least resistance. it wont split 4 ways. now it the plug had multiple platinum electrodes in the center, and the same amount of grounded electrodes, that would be a hella plug.


NAH2323
--- germans cant wire ****.

 

Most likely MAF Once the fuel pressure is found to be good. I tried several cleanings, Eventually replaced and no more 171,174's

 

What it really means is that the fuel trim was increased to it's limit and the O2 sensors still read a lean mixture. The most common problem on your truck for these codes is a bad elbow in the PCV hose back by the throttle body. Check for a vacuum leak here before throwing parts at it.

Other likely problems include fuel pump, fuel filter, injectors, front O2 sensors, MAF sensor.

 

Thanks everyone for your replys!!

I didn't trust anyone from AZ enough to actually start throwing money and parts at it. I knew I was in trouble when he had trouble pulling the code for 5 mins. I actually had to reach into the truck and start it up for him.

So, I took it to the Forums. And like Steve said, this guy from AZ was braindead. He had the personallity and mental capacity of a grape. And to boot, he was the store's GM.

Now you people here, on the other hand, and as the younger generation would say, you are da bomb!

Thanks again for all of your input.

Dave

 

As I recall. those are all qualifications to be an AZ store manager....

Steve