Join Date: Dec 2005
Location: South Florida
Thanked 6 Times in 5 Posts
2003 I4 idling problem, code P0507
I haven't started this car in 6 weeks, I went to start it a week ago and the battery was dead. Called a friend over this weekend and got a boost, she started right up. As we were putting the boost cables away, the engine started idling weirdly. Got in it and saw the needle bounce from about 1100 RPM to 2200, the drop, then as soon as it got to 1100 bounce back up again, sounded like someone was revving it. We decided to drive it anyway to charge the battery, got on the highway and drove about 30-35 miles, at RPMs over 1100 it was just its normal self, no problems on the highway in any gears, hit 85 at one point, no prob. No check engine light at this point. We thought maybe the problem would clear up, when we got off the highway and took it out of gear it started doing it again. We parked it and went to a restaurant, 2 hours later we came back. She started by herself (yay, the battery got enough charge!), bu the problem still existed. Drove back the same distance on the highway, again no probs on the highway, I tried to pull codes while my friend was driving her and there were no codes.
JUST as we got to my house, the last light before pulling into my complex, she started doing it differently, very quickly between (I think) 1400 and 1700 RPM, whereas before it was between 1100 and 2200 and shouded like a vroooooooom, vroooooooom, now it was a vroom, vroom, much faster, and the tach needle looked weird bouncing up and down in such a narrow range. CEL did come on at this point. I parked it w/in 3 minutes of CEL coming on and then pulled the codes again, P0507 came up as the only code. In the book and on the net, P0507 is listed as
P0507 - Idle Control System RPM Higher Than Expected
Duh! I could've told you something is wrong with the idle. What do you guys think this is? Some sort of sensor that went "stale" in 6 weeks of sitting there? The car has been extremely reliable, has 60K now, I got her at 18K 2 years ago, no issues whatsoever, had a bad O2 sensor once and that was it over this period. It almost seems like the computer thinks the engine's gonna die when it drops toward 1100 RPM and it accelerates to keep it alive. When coming out of gear it initially went to 3100-3500 once or twice, then settled in a fixed 1100-2200 pattern, until the very end when it switched to the fast frequency of 1400-1700 RPM.
Note that I used to drive the car ~2000 miles/month prior to not even starting it once in 6 weeks.
'03 Accord DX I4 5MT
RSX-S 17s on 225/45R17
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