I have a couple codes P0335,P0385,P0171,P0174. My car idles rough, when at stop lights car dies but starts backup. Car runs great down the road

What make , model , year and engine size. ?

P0171 & P0174 are lean codes.this can be cause by a vacuum leak. One of the symptoms is a ruff idle when cold.

You can listen for it or you can have it smoke checked by a shop. Most common causes are intake plenum gaskets and rotted PVC hoses.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

fix the first two
clear the codes see what is left

P0340 Camshaft Position Sensor Circuit Malfunction

P0171 02 sensor
System Too Lean (Bank 1)

if no better . these are unusual codes

P0106 Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem

P0304 Cylinder 4 Misfire Detected

P0219 Engine Over Speed Condition

fault code source


Complete List of OBD Codes Generic OBD2 OBDII Manufacturer Car OBD...

yea that's a electronic problem its probably a sensor

Try Maf sensor,(Mass air flow)
Then try tps sensor, (throttle position sensor)
Unable to answer exactly without looking up codes

P0171 and P0174 are lean codes. There is likely a large vacuum leak or the MAF is bad.

Try starting the car and wiggling the connector for the MAF sensor. Also try tapping the MAF sensor. If the idle changes or the car stalls replace the MAF sensor.

The second shop should recognize that these codes don't have anything to do with the ignition module.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

P0171 System too Lean (Bank 1)
P0174 System too Lean (Bank 2)
P2106 Throttle Actuator Control System - Forced Limited Power
P0355 Ignition Coil "F" Primary/Secondary Circuit
May be your car run normally now, but you must check and repair the fault in advance.
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MaxiDiag Elite MD802

click on the below links for code details.
P0106

P0121

P0171

P0174

P0335

P0340

P0385

P0442

P0506

P0507

P0601.

all of the above codes seem to have a common cause, they all list a bad ecm (computer) as being a cause, and the last code P0601 points specifically to a bad computer. sorry for the bad news, hope this helps.

Very common problem is about a dime size hole wearing in the rubber elbow on the PCV valve located on the driver side rear of the intake manifold.

The P0420 code is a Catalytic converter efficiency code check the compression.Swap the #1 injector to a different location to see if the code follows.Test the coilpak. A cracked exhaust manifold is the most likely cause p0171 and 0174 Induction air leaks, vacuum or some kind fuel restriction, weak fuel pump, restricted fuel filter etc.You also could have an exhaust leak near the upstream o2 sensor. If youtake it in they will probably use smoke to find out where the leak is.