Engine stalling

[emd645e3]

I tried a search but couldn't find anything. Kinda suprised. Anyway, when the radiator fan comes on, the engine starts bogging at idle, and sometimes dies. I thought it may be the increased load on the alternator, but one fan can't be that bad. Funny thing is, it will idle normally if I switch the A/C on and both fans run, but I guess there's some kind of high idle when the A/C is on? Also, I've got a wierd idle surge that I havent been able to figure out yet. Sometimes it idles normally, but when the car is moving slowly (like backing out of a driveway with the clutch in) it will start to surge. When It doesn't, I've tried to lower the idle down to normal, because it now idles at around 1100 RPM, but if I do that it will either stall or start surging. The ISC is good, I haven't done a boost-leak check yet though. It also smells like its running really rich at idle, too. Could it have something to do with the oxygen sensor?

 

[grnchevyz]

If it hasn't been replaced yet, I'd look at the front O2 sensor. As for the bogging when the fan kicks in, I'd definitely check voltage output on the alty before and during the fan kicking in. If there's a drastic difference, then I'd check wiring on the fan for exposed wires that could short out.

 

[emd645e3]

Thanks. I have a new o2 sensor, just haven't gotten it in yet. I'll put it in tomorrow and see what happens. New plug wires coming too, maybe that'll help out too somehow.