Q: Truck bogs out under load

asked by on

I've replaced the plug wires, coil packs, throtle position sensor, fuel pressure sensor, fuel filter, and cleaned the mass airflow sensor, but the truck still bogs under load. I no longer have any codes due to my battery dying but the two codes I remember are p0171 and p0174. If it helps I do have short and long term fuel trim numbers at idle and at 2500 rpm... At idle STFT bank 1 =1.6% -10.2%... Bank2 = -2.3% - -3.9% LTFT Bank 1 = 2.3% - 3.1% Bank 2 = 9.4% - 10.9% and at 2500 rpm STFT Bank 1 = 14.1% - 21.1% Bank 2 = 6.2% - 9.4% and LTFT Bank 1 = 14.8% - 16.4% Bank 2 = 18.8% - 19.5% . I must also mention that my egr valve tube that attaches to the exhaust manifold has completely rusted away. Could that cause lean mixture codes? I look forward to hearing from you soon. Thanks Bruce. P.S note the STFT Bank 2 were both in the negative at idle.

My car has 150000 miles.
My car has an automatic transmission.

First, the EGR tube rusted away will cause excessive air to get into the exhaust and cause the O2 sensors to read erratic. The main reason you most likely have a mass air sensor that is not reading correctly for the altitude you are at. You should check the mass air sensor with the key on and engine off to see if the barometric sensor is reading the correct altitude. If it is reading above 10,000 ft, then replace the mass air sensor. Disconnect the battery for 10 minutes to clear fuel control then road test for problem. If you need a diagnosis, a certified technician from YourMechanic can come to your car’s location to inspect the loss of power and advise you on repair.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Truck bogs out under load

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: power door lock on drivers side not working

Hi there. It really depends on what is actually damaged which would determine the ballpark estimate for repairs. This type of problem can be as simple as a broken fuse or electrical relay or as complex as a damaged power...

Q: Car runs rough - 1995 Cadillac Fleetwood

Hi! Sometimes a bad spark plug wire can result in what you are experiencing. If your vehicle is due for any scheduled maintenance (based on mileage), such as a tune up (new spark plugs, spark plug wires, distributor cap and...

Q: Cruise control broken

Hi. Cruise control systems only engage past about 35 mph, so make sure that is not the issue. Other issues that can sometimes interfere with the cruise control are brake lights that may be having connection issues. The system uses...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...