Our 2004 GX470 with 180,000 miles has suddenly started to run rough at idle and sometimes stall. I have not driven it anywhere like this, since it can barely idle. It started yesterday morning, when I started it for the first time after it had been parked for about 10 days while we were out of town.
It initially started up and ran fine, but I remembered I left something in the house, so I turned it off, went back in the house, came back out, tried starting it again and it wouldn't fire. The engine would turn over just fine, but it never started. The CEL came on and I scanned it with Torque and got only a P0335 Crankshaft Position Sensor A Circuit code. I went under the car and removed the crankshaft position sensor (one of the most awkward jobs, btw), and tested it according to the FSM. It tested OK but I swapped in a new sensor anyway just to see if it would make the car start. When I tried starting it again, it did the same thing as with the old sensor, cranked but didn't start. So I put the original sensor back in, cleared codes, and saved the new sensor for another day.
When I tried starting it after re-installing the original crankshaft sensor, it started fine, but after 10-15 seconds of idling, it stumbled and died and the CEL came on again. I scanned it and this time the only code I got was a P0230 Fuel Pump Primary Circuit code. So I went to the fuse box and swapped the relays around, and tried starting it again, but it still didn't idle smoothly. I cleared the codes again. Tried starting it a couple more times, and it would only run for 2-3 minutes at the most before stalling. Scanned codes again, and this time there are none.
The engine runs like when there is a bad MAF sensor, bad gas, or a bad coil pack. I cleaned the MAF sensor and the throttle body, and checked all the connectors on the coil packs just to be sure. I scanned it again, this time with TS and still found no codes. The TS live view shows intermittent misfires on all cylinders in roughly equal numbers, so it doesn't seem to be just one bank that's having problems.
Currently, the CEL is off. If I scan for codes, there are none, but it still runs terrible.
Any suggestions on what I should take a look at next?
UPDATE: It looks like the problem was caused by the sensor wire getting rubbed through by the serpentine belt, see pic below.
It initially started up and ran fine, but I remembered I left something in the house, so I turned it off, went back in the house, came back out, tried starting it again and it wouldn't fire. The engine would turn over just fine, but it never started. The CEL came on and I scanned it with Torque and got only a P0335 Crankshaft Position Sensor A Circuit code. I went under the car and removed the crankshaft position sensor (one of the most awkward jobs, btw), and tested it according to the FSM. It tested OK but I swapped in a new sensor anyway just to see if it would make the car start. When I tried starting it again, it did the same thing as with the old sensor, cranked but didn't start. So I put the original sensor back in, cleared codes, and saved the new sensor for another day.
When I tried starting it after re-installing the original crankshaft sensor, it started fine, but after 10-15 seconds of idling, it stumbled and died and the CEL came on again. I scanned it and this time the only code I got was a P0230 Fuel Pump Primary Circuit code. So I went to the fuse box and swapped the relays around, and tried starting it again, but it still didn't idle smoothly. I cleared the codes again. Tried starting it a couple more times, and it would only run for 2-3 minutes at the most before stalling. Scanned codes again, and this time there are none.
The engine runs like when there is a bad MAF sensor, bad gas, or a bad coil pack. I cleaned the MAF sensor and the throttle body, and checked all the connectors on the coil packs just to be sure. I scanned it again, this time with TS and still found no codes. The TS live view shows intermittent misfires on all cylinders in roughly equal numbers, so it doesn't seem to be just one bank that's having problems.
Currently, the CEL is off. If I scan for codes, there are none, but it still runs terrible.
Any suggestions on what I should take a look at next?
UPDATE: It looks like the problem was caused by the sensor wire getting rubbed through by the serpentine belt, see pic below.
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