Fast idle cold start 2k rpm 03 D2

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hamhockracer
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Posts: 1
Joined: Tue Jun 11, 2019 8:39 pm

Fast idle cold start 2k rpm 03 D2

#1 Post by hamhockracer » Wed Jun 12, 2019 2:23 pm

I have been having a tough time diagnosing this issue:

on cold starts RPM will race up to 2K then jump up to 2100 and back down or settle down to 1200, truck otherwise runs okay.
TPS appears to be working fine
IACV was cleaned and tested working
MAF sensor was replaced
Plugs were replaced
O2 Sensors were replaced
Plug wires were replaced

Problem continues

Vacuum is 14.5 inches and steady on idle. If the engine is a little bit warm it starts fine and reaches 1200 RPM like it should. My Hawkeye shows that the the high idle is indeed the target RMP of the engine, under what conditions would the truck want to start at 2k rpm?

What is it about the cold start has the engine racing up to 2k? I have some evap codes: P0171 and P0174 but I dont know if they are related as I have been unplugging vacuum lines here and there. Any advice you could offer on places to start would be amazing.

landcrabmechanic
Hot Manifold
Posts: 240
Joined: Thu Jul 19, 2018 4:55 pm

Re: Fast idle cold start 2k rpm 03 D2

#2 Post by landcrabmechanic » Wed Jun 12, 2019 2:40 pm

These codes are fuel codes.
Bank 1 lean and bank 2 lean.
You maybhabe an exhaust leak.
P0174
This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles. ... Basically this P0174 code means that the upstream oxygen sensor in bank 2 reporting a lean condition (too much oxygen in the exhaust.
P0171
P0171 is a diagnostic trouble code (DTC) for "System Too Lean (Bank 1)".

radio_05
Gently Used Condition
Posts: 76
Joined: Thu Oct 04, 2012 2:19 pm

Re: Fast idle cold start 2k rpm 03 D2

#3 Post by radio_05 » Sat Jun 15, 2019 12:52 am

In an older F150 pickup, your symptom would be caused by a gummed up throttle body without generating any engine codes. It would be resolved by taking off the inlet, and spraying with throttle body cleaner.

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