P0171 and P0174 codes
Thread Starter
Instructor
Joined: Oct 2022
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P0171 and P0174 codes
Hi folks,
About 3 weeks ago my check engine lit up randomly. I thought it's the usual fuel system small leakage code so I didn't hurry to read the ECU, until it went away on the next 2-3 trips. Then it came back this week and I read it out immediately. I got P0171 and P0174 codes. The car was acting as always, no dropping of rpm or bad idle, nothing. I deleted it and it hasn't came back yet.
What do you think might be the cause?
The car is tuned with catless lt headers and factory oiled K&N air filter (I put it in ~3000kms ago).
About 3 weeks ago my check engine lit up randomly. I thought it's the usual fuel system small leakage code so I didn't hurry to read the ECU, until it went away on the next 2-3 trips. Then it came back this week and I read it out immediately. I got P0171 and P0174 codes. The car was acting as always, no dropping of rpm or bad idle, nothing. I deleted it and it hasn't came back yet.
What do you think might be the cause?
The car is tuned with catless lt headers and factory oiled K&N air filter (I put it in ~3000kms ago).
Moderator, Tech Contributor
Joined: Sep 2013
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From: Cape Coral, Florida
If both bank fuel trims are elevated and if running at 3000 RPM decreases them you have a vacuum leak...if fuel trims are near 0 at idle but increase under load you have either a fuel delivery or MAF issue...this has nothing to do with your EVAP system (small leakage)
Thread Starter
Instructor
Joined: Oct 2022
Posts: 131
Likes: 7
