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Hello All, this 89 Blazer has a 2 second crank to start up, idles well and accelerates well. Has an intermittent off idle stall after extended idle. With a labscope, checked coil primary pattern (white wire from coil to distributor) both signal wires to PCM ( purple wire and white wires) 3 channels at onc. The secondary ignitin pattern and both injector patterns. The pickup coil holm reading was well within spec. TPS sweep had no drop outs. Purple signal didn't look uniform as the white wire. IAC seemed to be sticking causing a high idle at times but holm readings were well within spec. Coil holm readings were well within spec. Fuel pressure reading at idle and 2500 rpm within spec,and to tee in with fuel filter removed took ingenuity. I've replaced the ignition module, the IAC valve, the distributor cap and rotor and the fuel filter. The SUV still has intermittent stall off idle after extended idle weather in park or in gear. Ignition timing is a 0. The only thing I see is the distributor hall effect is rusty. The parts I replaced were defective but getting costly, I don't want to condemn the distributor but it's next on the list. Hope this doesn't make anyone laugh, but if it does, hey it's a learning experience, thanks. Also condition exists with the EGR disconnected and the injection pattern with a shop light has a good concave appearance.
Last edit: 4 years 3 months ago by Smoggyboy. Reason: adding information
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