P0174........... Still

[HAND HERPES]

I reset the code twice last week and once today. The code keeps coming on at the same EXACT spot every time when I'm coming home from work.

Attached below is a picture of the hill. The code triggered on this hill 3 times already about a little more than mid way up. What do you think it could be? Why does it trigger when going up this hill??? Thanks


(will post pic when I find it on Google Maps)

EDIT: Picture of hill doesn't matter, there is no street view lol

[Fastbird]

If it's throwing the code at the exact same point, I have to wonder if it's something in the MAF table for that particular area that you're putting the car in going up hill. Granted, you're a 3.8l right? Is that MAF or SD? If it's SD then I can for sure see it because it's probably a VE cell that's a tad lean causing a quick errant reading.

[HAND HERPES]

If it's throwing the code at the exact same point, I have to wonder if it's something in the MAF table for that particular area that you're putting the car in going up hill. Granted, you're a 3.8l right? Is that MAF or SD? If it's SD then I can for sure see it because it's probably a VE cell that's a tad lean causing a quick errant reading.

Yup 3.8L

Yes, the exact same spot triggers the check engine light. It's weird lol

SD???

It has a MAP sensor, should I replace it?


Also, the car feels like it has no power when you first start it up and go. I let it warm up for 2 minutes before I take off. I get out to the stop sign at my work and it hesistates to go but once it gets moving its fine and it doesn't do it anymore.

[Madman337]

Yes, the exact same spot triggers the check engine light. It's weird lol

SD???

It has a MAP sensor, should I replace it?
You need to check your components before throwing parts at it first.
SD= Speed density
MAF= Mass air flow
This is pulled from pcmforless............
Mass Air Flow Mass air flow sensor equipped cars fuel either directly from or by a blended model of both mass air flow and speed density calculations. The MAF sensor is located somewhere in the intake stream typically away from sharp bends and typically at least 8-10 inches away from the throttle body however these rules are not always followed. There are several different types of MAF sensors but for most GM applications it is a frequency biased "cold-wire" sensor that generates a signal between 0 and 15k Hz. MAF sensors read not just airspeed but the relative mass of the air which eliminates pressure and temperature as variables. They are usually positioned to sample from the middle of the intake tubing which should give the best average reading.
Since the MAF sensor samples from a specific spot in the inlet tubing changing the airflow in or around the sensor requires recalibration of the MAF sensor. Changing the airflow around a MAF sensor can be caused by a change in size of the intake plumbing, bends before or after the MAF sensor, and changes to the MAF housing.
Several applications that use MAF biased strategies also use Speed Density as a backup or for a blended fuel calculation. They also use Speed Density as a sanity check for MAF readings.
Advantages

Typically more forgiving and easier to tune
If the MAF sensor has been calibrated typically fueling remains consistent as modifications change. It can be said that the MAF equipped cars are a little more forgiving to new modifications
Since the MAF sensor measures air mass directly it can be said that a MAF equipped car might stay in calibration as the engine wears or in extreme environment changes (however this is not normally a concern for well tuned speed density applications).


Disadvantages

Sensitive to changes to the intake plumbing
Can be fouled by becoming dirty. Once fouled MAF calibration is skewed
Sensitive to cam reversion on large cammed cars. The MAF sensor isn't directional so air pulsing back and forth can affect repeatability and reliability.
Limits on performance. Most systems can not read at higher horsepower levels.




Speed Density
Speed density systems calculate the density of the air first by measuring the temperature of the inlet air and manifold pressure. With the density of air known the engine controller then looks up how much air it expects to be moving at a specific engine speed and manifold pressure. This is done in the Volumetric Efficiency table or VE table. Traditionally the VE table is 3D and has two axes Engine Speed (RPM) and Manifold Pressure or % Load. A engine that is 100% efficient moves exactly its displacement every two rotations in 4-cycle engines.

Advantages

Less restriction in the intake tract
More freedom in the intake tract
Able to measure air consumption on very high horsepower builds where a MAF sensor might be limited.
Able to read boost if equipped with a greater than 1 Bar map sensor
Free from errors encountered in MAF fouling.
Works better with large cams where reversion affects reliability.


Disadvantages

Is a little more difficult to tune
Relies on a well tuned Volumetric Efficiency Table
Less forgiving to new modifications to the engine
Might have errors in large weather changes however a proper tune makes this minimal if any error.

[firebird_1995]

As sean said, I would agree that the increased load is causing the code to set.

[HAND HERPES]

It's an aftermarket MAP sensor from a junkyard, should I get a GM one?

I'm not sure what you guys are getting at? This is normal to trigger a lean code going up that hill?