2003 SES OHC "U" total loss of power

[SES Dad]

Will confirm fuel numbers as soon as possible.

Assuming the P0171 lean code was there for a while, question is why?
Based on the short length of progression from 'slight hesitation under load' to full lack of power, would guess that the coil was starting to go and then finally went quickly. When it did go, my daughter was driving in town only. With me trying to drive it home, not sure if I ever got over 40-45 mph either. That could explain the lack of mis-fire codes. Guess we'll see soon enough.
Thanks again.

[Breeves002]

Behlinla actually recently explained this to me. So oxygen sensors measure the amount of oxygen in the exhaust. If there is a lot of oxygen it adds more fuel to compensate and burn up that oxygen. If there is very little it reduces fuel.

So since two cylinders were misfiring, it was just pumping the oxygen out into the exhaust causing the o2 sensors to go to high voltage causing your fuel trims to shoot up. The PCM thought there was a lot mor O2 going through, but it assumed all cylinders were firing.

Your scan tool should be able to tell you what monitors have been completed.


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[behlinla]

Yes, since the oxygen is not being used up due to a lack of combustion (misfire), the O2 sensors sense this as a false lean condition. Your previous lean code might or might not have been in conjunction with a misfire.

[Breeves002]

We're gonna find out soon!


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[SES Dad]

That is why my first statement was 'time to ask the experts'. You guys really helped me out on this one. I really appreciate all you do. I'm sure all the other 'forumites' do to. Please keep up the good work.

[Breeves002]

Being called an expert feels good for me! 6 months ago I didn't know that much at all! Would have had no idea what to say here.

Just let us know if that lean code is gone! We want to make sure you don't have any additional issues!!!

P.S. PLEASE vote for January COTM if you have not already! Rep is also appreciated (rep button bottom left of this post).

[SES Dad]

Well guys, the coil pack fixed the problem!! The old one had a clearly visible crack under the two non-operating positions.
I put on the new DPFE hoses and sensor and they stayed put as well.
Had it out for a test drive around town and on the highway at 70+ mph.....no problems.
I still don't have access to a code reader to do any other checks that we discussed, but still plan to go through it to make sure everything is functioning properly.
I can't thank you both enough for helping me with this. I also feel much better knowing my daughter has a reliable car to use.
I have also learned to not ignore the CEL....if it is on, it is telling you something.
Keep up the good work.
Rich

[behlinla]

Glad the coil did it for you (I was pretty confident it would). Hopefully you did the 3+ coast-downs so the misfire monitor can complete and so you'll get a CEL if you have another misfire. You should also change your oil since you probably have fuel dilution. After that I would take it for a 30+ minute trip on the interstate just to get everything nice and warm to work out any fuel vapors.

[Breeves002]

^
+1

Congrats. Happy to help you find out any problems in the future! Yes get that misfire monitor completed. Just coast from 60-40mph 3 times (no brake). Should get that set.

Let us know when you get the fuel trim #'s as well.

[SES Dad]

Guys,
Sorry it took so long to get some additional info....work gets in the way.
No issues found so far. She has been driving it for 2-3 weeks now, mostly around town. We had it out on the interstate several times.
I hooked up the scanner just to check the other data.
All fuel trims were the same at 61.7%; fuel pressure recorded at 46.9 psi
Do these numbers look OK?

I got a call yesterday that she just lost her one-and-only ignition key and fob.
I'm glad I still have new things to keep me busy.

Thanks again for your help.
Rich