Q: Engine Power Reduced TPS

asked by on

My 2008 Chevy Express 1500 is indicating Engine Power Reduced and Service TPS (Throttle Position Sensor System) was going into Engine Power Reduced mode. I have a faulty catalytic converter and my oil shows 0 % for being effective. When I’m on the highway and driving on a flat stretch of road I can get my car up to about 50 mph. But when I slow down or stop it has really low power when I take off again. When going up any hill or slight incline it is very, very slow. When it’s idling it runs and sounds like a tractor. It vibrates and the engine rattles the whole front end of the car. If I accelerate a little, it quiets down the vibrating. I was told by someone that one of the sensors in the Catalytic Converter, or in the emission system has to do with the throttle, (throttle position sensor), and because it’s bad, the system doesn't know how much gas to give or how fast the car may be going because of not knowing how much the throttle is open when the engine power is reduced as a safety. Can a faulty Throttle Position Sensor system and a faulty catalytic converter be the cause?

Hi! Yes the throttle position sensor could very well be the cause. I highly doubt that it is the oxygen sensor though. When the throttle position sensor goes bad the engine will put itself into reduced power mode.

I was working on a Chevy Trailblazer the other week with the same display message. We ended up tracking the problem down to a bad throttle body. The throttle body is electronically controlled and the throttle body electrical motor would become stuck sometimes during vehicle operation and cause it to go into reduced power mode.

A technician should test the movement of the throttle body and ensure that the throttle body plate can move back and forth freely. I also suggest testing the throttle body input and output with a multimeter. Feel free to contact a certified mechanic who can perform these checks and properly diagnose your loss of power if you need some assistance. Once this is done, the problem will be evident and the mechanic can perform the necessary repairs.

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. Engine Power Reduced TPS

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: How do I set or cancel the engine immobilizer?

The engine immobilizer is an important safety feature that keeps your car from being stolen. The system immobilizes the engine to keep anyone from using unauthorized keys, or hot wiring your car to start it. The engine immobilizer will automatically...

Q: Stalls while applying throttle. Already changed two warm up regulators

Hello. I think you may have a problem with the cold start valve not dumping the proper amount of fuel to allow the car to start and remain running on a cold start. The distributor should be checked as well...

Q: Oil level drops during idling

Paying close attention to your gauges while driving is a great way to monitor your vehicle and ensure that it is running efficiently. I have actually come across this concern during other experiences with Chevy Express vans. When the van...

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...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
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.