Recently started running poorly in the cold. Once the engine warms up, it runs fine. Pretty consistently throws the p0130 and p0133, and randomly throws the p0401 mixed in. Changed the o2 sensors last night with no improvement. When cold the front sensor will read 0.0 to about 0.3 and when warm it stays near a 1.0 reading. The rear sensor runs pretty much always at 0.0 with small fluxes to 0.1. Is all of this an indication that the EGR is stuck? If so, how do I tackle it? Can I clean it or is it just a bite the bullet and buy used or new? Any thoughts are appreciated!!
codes, now a no start
- Thread starter Alan Jones
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nukegoat
Should have bought a Jeep
bad cat? rear o2 sensor should do something
LC4LIFE
Supporting Vendor
How much have you driven it since the new O2's? You need to complete a full drive cycle for the ecm to clear any codes.
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What brand sensor?
If you buy new O2 sensors .... DO NOT buy the cheaper Bosch sensors. You will throw the O2 code forever. The truck will run just fine, but the code is your co-pilot.
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On the one we are working on, replacing the POS Bosch upstream O2 sensor with a Denso 234-4157 solved the P0130 & P0133. A 4.7K ohm resister across the thermistor connector solved the P0401.
- Thread starter
- #9
Update; all vacuum and intake hoses are practically new and are good; removed, cleaned, and reinstalled egr. As for the rear o2 sensor, I installed he spacer in i awhile back to override some of the known emissions issues and it has been running like a champ for over a year. What I can't figure is that this issue is relative to the cold, and once the whole system warms up, there is no idle issue. As long as it is still warm, it will crank and run just fine. Once it sits long enough to get cold again, the issue returns. Any chance there is a connection to the TPS or IAC sensor?
Oh wow!
Did you at least clean the O2? There might be enough carbon build up for it to be less sensitive enough to throw the code, just take them out and use wire brush. I would just replace them both with amazon Denso ones. 100 bucks and my cruiser runs noticeably better.
Did you at least clean the O2? There might be enough carbon build up for it to be less sensitive enough to throw the code, just take them out and use wire brush. I would just replace them both with amazon Denso ones. 100 bucks and my cruiser runs noticeably better.
- Thread starter
- #11
TPS was fully clean and within proper adjustment. I am having a hard time accessing that stupid lower screw on the IAC.
nukegoat
Should have bought a Jeep
So you removed your rear o2 sensor so the computer cant adjust long term fuel trim and its been performing worse now? Why not let the computer do its job?
- Thread starter
- #14
pulled and cleaned IAC and no change. still rough on cold start, still runs well at normal operating temp. o2 sensors are clean as both are new. as for the rear o2 sensor, it is a common fix to use an extension. i can pull it and see if anything changes but it has run exceptional for over a year with the extension in place. what other sensors could be in play?
- Thread starter
- #15
and based on some other threads, i unplugged both o2 sensors with no change. must be a sensor
nukegoat
Should have bought a Jeep
Ah. Just a wire extension? I thought you removed it.
- Thread starter
- #17
any other sensors that might be in play? pretty frustrated in VA
- Thread starter
- #18
Any chance the fuel pump resistor could cause this issue
inkpot
SILVER Star
I believe extension means spacer. An old trick to beat some smog problems. It would be worth pulling it off and testing without extension. can always replace it for testing as needed?
Sounds like there is a problem when the system is in open loop. Maybe there is a problem with a temp sensor? I had to remove the throttle body to clear a plugged port to the modulator valve and bypass the intake port with hose and replace modulator valve and solenoid valve to rid my p0401. The rough running cold issue might not have anything to do with the O2 sensors as I don't believe the computer is reading them until a certain engine temperature is measured. Is it loading up running rich or leaning out when its warming up?
