Suspendedhatch, while all of what you say is all great info, you don't mention lean-burn anywhere. To me it seems like the car has a problem with lean-burn cruising, and that it bypasses the (faulty) LAF and goes out of lean-burn when the check engine goes on. It would also explain why it runs smooth while accelerating, you're not running in lean-burn until all conditions are met: speed (VSS), TPS, and whatever else the computer monitors for a LB cruise. I think a new LAF should fix his problems, I know you said that it needs to be replaced, but I couldn't figure if you thought if that would fix his problem or not. I'm no expert on honda fuel injection, just saying what it looks like IMO, so correct me if you see any flaws in my logic... or if we're both saying the same thing here.
Big oil execs making 32mil a year and we're paying upwards of $4 a gallon.. Hubberts peak you say? Oh ok, I believe you.
I paid $3,000 with 133k miles. Decent shape. Might have over-paid a little, but around here they don't last, if you can find one. All the young bucks line up to get their hands on them. I basically had to buy this one sight unseen because there were dozens of inquiries after the first day it was for sale. I have found 5 more VXs within a few hundred miles from home for sale since buying this one. Each one sold before I had a chance to make an offer, and I watch pretty closely. If I can find a better one in terms of condition, I'll buy it because I know I can sell this one the next day!
OK. I checked my plugs and had NGK ZFR5J-11, and gapped a bit too small. Got excited thinking that must may be it. I have a parts store just a few blocks away, so I got the ZFR4F-11, gapped them correctly, and went on a test drive. Results:
Same symptoms, but then at around 5 miles out, the CEL came on and it immediately ran smooth and I could hold the speed with no problem, just like the only other time the light came on. Went 5 more miles, stopped, shut it off. Then drove 10 miles back and CEL did not come on and ran rough again.
Please listen to me. It's your o2 sensor. My car did the exact same thing, except mine never got so bad that the CEL came on. You can check the code using a paper clip. Have one ready and the next time the CEL comes on use a paper clip. I don't remember the exact procedure, but if you search "CEL o2 sensor paper clip" without the quotes on these forums you'll find the answer! You're looking for code 48. good luck.
SVOBoy said: Find the little blue plug tucked up under the dash on the passenger side and jump it with a paper clip and then watch the CEL flash. Long = 10, short = 1, tell us what the code is...
There should be a blue one with 3 pins and a blue one with 2 pins. Put the two ends of the paper clip in the jumper with 2 pins.
As suggested, I did the paperclip trick to flash the code on the CEL. 48 was the result. So, I've been surfing the net for O2 sensors. Best prices I've found are on eBay. One for $80 that claims to be an NTK 5 wire and waiting to hear back to confirm, and another for $170 who did reply back saying it is an NTK 24300.
If a new O2 doesn't solve the issue, I've been reading about all kinds of suggestions on other threads suggesting replacement of the TPS, clean the EGR, and vacuum leaks as potential culprits. I suppose I could change the wires, cap, and rotor while I'm at it.
Great site. Thanks for all the input from all of you!
I ended up getting a Bosch 13246 on eBay for $97. Fixed the problem. I was averaging around 46 mpg. But then it dropped to around 42 mpg after installing the new O2. But the last test came out at 56.4 mpg driving 200 miles at about 75% highway. I'm wondering if it takes a few hundred miles for the computer to adjust to the new O2? Now it seems to be on track.
If the code is for O2, and you have the right ECU, and you haven't modified or damaged the wiring, replace the O2. Simple.
What is there to say about lean-burn? People learn one neat little thing about a car and they focus on that and nothing else. Every time there's a problem with a VX someone says "is it the lean burn"? The rest of the Hondas they say "my car is slow, is my VTEC broken"? Pretty silly.