multiple codes and rough idling 2004 throttle position se...

Q: multiple codes and rough idling

asked by on September 05, 2017

Car was fine and then had a loss of power, and the EPC, traction control and engine light came on. It idles rough (constantly going up and down). The codes that came up were P0171 P0222 P2637 P0638 and P0121. We've changed the spark plugs, New 100 & 428 relays, changed the small fuses, New fuel filter and replaced the throttle pedal (gas pedal) with no change. Could it be the throttle body or the MAF sensor? Bad wire? We're at a loss. When we changed the spark plugs there was oil on 3 of the 4 plugs.

My car has 90000 miles.
My car has an automatic transmission.

The first thing to check for in any drivability problem is air leaks. Any air that gets into the engine without being measured will lean out the system and cause problems. Look at all the rubber hoses and boots under the hood to be sure they are well connected and in good condition. Once you’ve ensured that these things are fine you can begin to address the codes. While the P0171 is a lean mixture code, and may be brought on by air leaks among other things, three of the other codes are related to the throttle body. VW has a lot of throttle body issues and I have changed many of them on cars with less than a hundred thousand miles so it’s not unlikely that you need one. But I wouldn’t run out and buy one just yet. They are pretty expensive and usually not returnable. It would be more prudent to have the car diagnosed. By contacting YourMechanic, you can have a technician come out to your home or office to check out your Golf and let you know what it will take to solve the problem.

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

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

Speedometer is stuck, and not sure if cruise control works.

The speedometer reading zero all the time could be one of two different problems. The first could be the speed sensor in the transmission has no output in the system. The other is a defective instrument cluster gauge. A technician,...

I have a 2012 VW Jetta SE and I was pulled over and the cop told me both my brake lights wernt working. So I bought some bulbs and

It sounds like you may have a weak battery, a failing voltage regulator or failing alternator. As you may know, the alternator charges the battery while the engine runs by generating amperage and recharging the battery while the engine turns...

P0011 and P0301 Code After Timing Chain Ticking Noise Fix 2004 Nissan Quest V6

Hi there - these codes indicate a mistiming problem with the camshaft for the cylinder bank which includes cylinder #1. This means that the cam timing is incorrect as a result of your timing guide repair. The repair requires disassembly...

Related articles

A Buyer's Guide to the 2012 Volkswagen CC
At At some point, most of us have to choose between the cars we wanted when were kids and the ones we need for our commute to the office or to pick up our own children. With the 2012 Volkswagen...
The Best Used Cars to Buy If You're a Rock Climber
If If you’re a rock climber, you want a vehicle that gets you where you need to go, even if the terrain gets rough. You may be living out of your vehicle at times, so you also want a rig...
The Difference Between a Throttle Body Position Sensor & Throttle Body Temperature Sensor
Though both part of the fuel injection system, the TPS and throttle body temp sensor monitor specific aspects of the fuel/air mixture.