Cel P0171

[dmention7]

I saw that one, but it seems to have gotten a bit threadjacked, haha.

 

[SpeedAdiction20]

ya by me mostly, but leex hasn't replied too much lately, he's still trying out the suggestions that we told him from what I have read..but it's all the same relative issues, and that one is more recent, you'll get more replies in that one

 

[HondaEat-R]

I'm not going to start a new thread, since there are already a million "P0171" threads.

A day or two ago I started noticing a VERY intermittent hiccup while cruising at mid-rpm, low load. Barely noticeable, just felt like a little gust of headwind or something. I noticed it about every 15 minutes or so today, and was going to check for pending codes when I got home, when sure enough the CEL comes on.

Other than the aforementioned hiccups, I have no symptoms--idle is smooth and even, vac at idle is 21-23inHg (no large or obvious vac leaks I can locate), no problems under load or in boost. I've only got a stupid narrowband sensor right now, so I can't say anything for certain about AFRs, but it's little "dance" hasn't changed at all. I've cleaned the EGR valve twice in the last 50k miles (at about 108k right now)

I had just cleaned the MAFS a few thousand miles ago, so I don't think that's it, but I cleaned it again today for good measure. Sounds like the next place to look is the primary O2 sensor?

Random misfire ? Run the codes and see.

 

[dmention7]

That's the code I was expecting, but the only code reported was P0171, with no codes pending.

I cleaned the MAFS last night and cleared the code. I noticed one more hiccup today, but that's it. Maybe it was just a dirty MAFS after all.

 

[dmention7]

Well it's not the MAFS... the hesitation is getting more frequent, but no codes reported or pending. I pulled the primary 02 sensor and cleaned it off with brake cleaner like someone suggested, but that didn't do anything.

I'm kind of at a loss as to where to start diagnosing, so if anyone has any pointers before waste too much time and money randomly cleaning this and replacing that, it would be appreciated!

 

[SpeedAdiction20]

did you say you cleaned the EGR? don't remember if you did, if not do that next.. and I mean really clean it, use a thin wire brush and let the carb cleaner soak in there for a while, and move the valve up and down by taking off the top sensor thing.. really get it clean and see if that helps

 

[dmention7]

I cleaned it this past fall (and again about a year prior). So it could conceivably need some TLC. It's on my list for this weekend when I start randomly cleaning and/or replacing anything I can think of. haha

 

[SpeedAdiction20]

oh, ya I guess if you cleaned it that recently, then it is less likely to be that.. but I dono, easy enough to just get rid of that variable by doing it again

 

[dmention7]

I poured 3/4 of a bottle of seafoam in the gas tank (mostly because I've had it fix stranger problems before!) and the car was running perfectly for about 3 days. Then just a few minutes ago, while accelerating from a stop sign on a residential street, for about 3 seconds the car felt like it was running on 2 cylinders. Then everything was back to normal for the last 2 miles till I got home. Sure enough I pulled a pending P0300 Multiple Random Misfires code.

The sheer inconsistency of all this makes me think it must be something electrical, but hell if I have a good idea what.

 

[SpeedAdiction20]

wow, that is strange... misfires are no good, weird msp problems, hopefully you can figure that one out.. have you changed your spark plugs anytime soon? couldn't hurt if there kinda old I guess

 

[dmention7]

Actually I just replaced them about a month ago, haha. Same NGK copper split tip plugs I've been using for years. A little searching seems to show that O2 sensors and EGR valves can cause the P0300 code, so we may still be on the right track here.

 

[SpeedAdiction20]

oh, ya actually my primary O2 sensor was causing some weird problems on my first msp, it was after a hot pipe coupler blew off (when I first got the WR hardpipes and drove it up the road with the crappy couplers they provide) it fried the O2 sensor really bad lol.. check that next I guess, I hold the little washer on it and shake it to see if it rattles, the ones that I have known to be bad rattle.. but if not then I guess should try to get a new EGR unless you haven't clean it(again I forget if you have cleaned it, and I'm in the middle of doing an essay, I just check on here every 30min or something to get my "fix" lol so I just don't want to re-read the previous pages).. the search continues hah