rob249
OBS Enthusiast
Still trying to get my 94' Yukon to stop missing at idle. I did a tune up before a long trip a few months ago, new plugs, wires, coil, distributor, and "rebuilt" the tbi. Truck was running great, except for the miss at idle when warm. I failed emissions, high HC, but the CO is quite low. An old GM mechanic suggested I check the EGR, which did have a leaky diaphragm. I replaced that, now Im getting a check engine light, code 34, which is MAP sensor high vacuum. Wondering if i have the vacuum line going to the wrong place, or if its just a bad MAP. Vac line is going from MAP to the back of the TBI. No codes before the new EGR. Any way to test the MAP? Should I just assume that sensor is bad? Maybe I have the vac lines incorrect? Please advise, and thank you.