Skip the auto shop - Our mechanics make house calls

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.

A: First, the EGR tube rusted away will cause ...

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?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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: Lost power to my front brakes but i still have power to the back.

Hello and thank you for your question. When you were able to bleed all four brakes FR, FL, RR, RL, then the proportioning valve is okay. If the valve was sticking, you would not be able to get any fluid...

Q: Rough idle start stalls

Hello. The symptoms you are experiencing can be caused by a wide variety of issues. Engines require 3 things to operate: fuel, spark, and air. If there is any issue with the supply or system of any of these three,...

Q: Engine erratic behavior, misfiring hard starting every now and then

Engine misfires can be caused by many different problems, but there are a few suspects that occur more than others. Generally, misfires are caused by either a spark or fuel issue or in cases, a combination of both. Spark related...

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.