Cross post...seems relevant (1 Viewer)

Mar 16, 2003
Trouble shooting 2F


Due to rust thru of old tube, I just replaced the EGR cooler to EGR valve tube on my FJ60 (86). Has certainly taken care of the "popping" and backfire I had prior to warming up.

Now, new problem... won't run well unless fully choked. Before replacement , truck ran very well. Truck starts easily, but just runs rough and seems to be on the verge of stalling unless I keep full choke.

Suspect vacumn problem?

I have the emission control repair manual, which I will start trouble shooting with this weekend. In the meanwhile, can someone confirm for me whether or not the high altitude compensation (HAC) valve, always draws air from the bottom tube open to atmospheric (ambient) air under all condtions. It seems to on mine, but the truck does seem to smooth out a bit when I plug that particular port. From the manual it doesn't make sense to me....

Thanks and cheers


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