Q: Car still runs bad. Replaced fuel and oil filter. Also replaced knock sensor and got an oil change. Car stalls and has slow speed.

asked by on May 30, 2017

I was getting the P0172 and P0171 codes when I got a diagnostic. I got the sparkplugs changed and it ran a little better. I got the fuel filter changed and the oil filter changed and it ran a little better. Then I got the knock sensor changed and it ran a little better. It still stalls and runs slow. It is also slow to accelerate. What else can be the problem? Could you provide a list of possible fixes to this problem?

My car has 204000 miles.
My car has an automatic transmission.

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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

transmission
It sounds like you are having a problem with your transmission's shifting mechanisms. Have the shift linkage checked to see if the cable bushings are worn out. A mechanic, like one from YourMechanic, can give your car's transmission an inspection...
8000 first oil change
If your manual says to change the oil (https://www.yourmechanic.com/article/when-should-i-change-my-oil) at 8000 miles then this is the official manufacturer recommendation. You have the choice to change the oil and filter sooner, but you will still need to monitor the oil level...
High idling, 8800 RPM
Hello there, 8800 is a very high idle. Most vehicles max out at between 6000-7000 RPM. If the vehicle idles at 800 RPM, then this would be considered normal in most cases, unless the idle fluctuates unusually. If the AC...
why does my battery keep going dead?
The best way to diagnose the type of issue your Hyundai is having is by beginning with using professional level test equipment to verify that the battery, charging system, and starter are all functioning correctly. These testers are widely used...
Crankcase ventilation hose, valve cover to intake? - Excursion 6.8 l
Hello - this piece is part of the crankcase ventilation system (https://www.yourmechanic.com/article/how-long-does-a-crankcase-vent-filter-last), and has a PCV valve underneath. It vents crankcase fumes to the air intake system for combustion, regulated by the PCV valve. This hose is available separately from...
Oil consumption
Hi there. I understand your concern. You can perform an oil consumption test similar to what I have performed while employed at the Toyota/Lexus dealerships. Perform a fresh oil change. Clean everything. Note the level on the oil dipstick. Zip...
I have been working on a lexus ES350 I'm getting codes p0300 p0174 and c342d and can't figure out what the problem is, can u help?
C342d relates to faults in the throttle position sensor (TPS) or the idle air control valve (IAC). Check the wiring to the TPS sensor and the IAC valve and test for high resistances which will show up as voltage drops....
Extreme negative fuel trims only when coasting, with rpm bounce
Fuel trim is a very valuable diagnostic parameter but to evaluate fuel trim, you generally check at fixed engine speeds namely idle, 1,500 rpm and 2,500 rpm, for about 30 seconds. If the sum of STFT and LTFT is less...
Car stalled. Engine light came on. But running fine the next day and the light is now off.
Hi Christine. Thanks for contacting us today. Typically when a progressive issue like you've described occurs, it's due to a clogged or damaged fuel systems component, such as a mass air flow sensor, dirty fuel injectors, dirty fuel filter or...

Related articles

A Buyer’s Guide to the 2012 Lexus GX 460
It It may be hard to believe, but luxury and adventure can go hand in hand – especially with the 2012 Lexus GX 460. From its luxurious interior with a variety of features to its high-quality build, off-road prowess and...
A Buyer's Guide to the 2012 Lexus IS
If If you haven’t heard of the 2012 Lexus IS, you’re not alone. This sports sedan is incredibly underappreciated. However, that doesn’t mean it’s not worth considering for your next car. Key Features The 2012 Lexus IS can be purchased...
A Buyer’s Guide to the 2012 Lexus LS 600h L
The The “h” stands for hybrid, and while you might hope to get greatly improved gas mileage for your effort to go green, that shouldn’t be your motivation for buying this model. The 600h L offers a mere 1 mpg...