Rough...hunting...idle July 11, 2011, 09:23:07 PM Car ran fine, no issues at all. No engine fault codes.Only thing I did was put the Mustang stock headers and offroad H pipe and lers on. I put new o2 sensors in (NTK) with longer wires to reach my stock harness.It now has a rough hunting idle, only when engine warms up.Ive bumped up the base idle and brought the TPS down to .98, it was at 1.08 after increasing the idle speed.I put new Motorcraft plugs and Ford racing wires.Base fuel pressure is 45psi, no fuel spitting from the fuel pressure regulator.Ive cleaned the EGR and IAC, were already clean.Vacuum holds steady at 21 inches.I got a code 91R, only fault code. Is it likely to get a bad O2 sensor out of the box? Could an exhaust leak at the header/Hpipe junction on the other side possible to cause that? The car smells fairly rich. Ive unplugged that sides o2 sensor and it seems to resolve most of the issue. What is the deal with this???????????? Quote Selected
Rough...hunting...idle Reply #1 – July 11, 2011, 09:33:37 PM Double check to make sure you didn't get the 02 wires crossed when you had them unplugged. Quote Selected
Rough...hunting...idle Reply #2 – July 11, 2011, 09:54:07 PM Im almost positive I didnt. That harness is so short, I dont see how I could have reversed them.Anyone know the wire colors so I can totally rule that out? Quote Selected
Rough...hunting...idle Reply #3 – July 11, 2011, 11:01:38 PM According to the 88 EVTM, the "Left" side is dark blue w/ light green stripe, the "Right" side is dark green w/ purple stripe, and both have a gray w/ yellow stripe and a black w/ light green stripe. I believe the "Left" side is driver's side. Quote Selected
Rough...hunting...idle Reply #4 – July 12, 2011, 09:37:37 PM My sides are correct. There was still a factory sticker saying "right" on the passenger side harness. Any other ideas? Quote Selected
Rough...hunting...idle Reply #5 – July 13, 2011, 09:26:44 AM Hmmm...can you hear an exhaust leak? It would be nice if you could plug in your old o2 sensors to rule that out, but that's not going to happen. Quote Selected
Rough...hunting...idle Reply #6 – July 13, 2011, 10:47:14 AM Maybe try disconnecting your battery for 10 minutes or so to CTRL/ALT/DEL the computer. Quote Selected
Rough...hunting...idle Reply #7 – July 13, 2011, 01:38:28 PM Quote from: flylear45;363359Maybe try disconnecting your battery for 10 minutes or so to CTRL/ALT/DEL the computer. Did this several times.I can hear what seems to be a pretty nasty exhaust leak. Can that cause this kind of havoc? Quote Selected
Rough...hunting...idle Reply #8 – July 14, 2011, 04:32:08 AM That might be it. Especially if it gets better when you unplug the sensor on the side that's leaking. Quote Selected
Rough...hunting...idle Reply #9 – July 14, 2011, 08:20:46 AM Thats the weird thing, the bank that the sensor says is lean, is not the side I hear the exhaust leak on ???????I unpluged the side that was not leaking and the idle cleaned up ??? Quote Selected
Rough...hunting...idle Reply #10 – July 15, 2011, 02:59:34 PM Update.Just fiddling around and put a new PCV screen and valve in. I tightened up the h-pipe-seemed pretty loose. I also switched the sensors from side to side. And Viola.................All seemed fine. I ran code and no more code 91R and the only faults were smog pump related, which I have deleted. Quote Selected
Topic: Rough...hunting...idle (Read 1111 times)
previous topic - next topic
