THe brother says its running fine since I repaired it (no idle...had an air line to the intake manifold that had come loose), but it is getting mileage like his truck, around 12 MPG. I read out the codes, and it is only setting a code for "speedometer" sensor. Well, I really didn't even think that was monitored by the Jetronic system, as I thought it only provided the signal to the speedometer. The wires to the differential-mounted speedo sensor were found broken when I repaired the vacuum leak, so I repaired the connections. However, the speedometer was still inop....once in a while it starts working, but not for long. SO I am thinking the bad connection may be at the instrument cluster, or the speedometer itself is bad. So I am wondering, since the ECU is picking up a fault with the speedo sensor, if I am wrong and it *is* a part of the control system....and maybe keeping the engine from going "Closed-loop" when up to temperature. I need to check to see if the engine is maybe stuck in closed-loop, because that might explain the poor gas mileage. How do I test for this? Hook up a timing light and see if, after the engine gets up to operating temp, if the timing is fixed in spite of revving engine, maybe? I think he mentioned it eating gas before it went down with the vacuum leak, actually! It may have never had normal gas mileage since he got it over a year ago. Thanks Geronimo
