Ok I started a thread titled "no start, not security system!" and got one hit and it was just a question. I think when people read the title they thought "newbie... do a search" Just so you know I have searched this forum as well as many others. I have not found a single problem that even comes close to what is going on with my Blazer. Ok enough crap, the problem. when the engine and ambient temprature are below 75* F. Now here's what I have done to it. I did all of this before the problem started. I checked the fuel pressure 60 when key turned then drop to 55. back up to 60 when running It has great spark and no codes. Cap, rotor, plugs, wires, MAP and o2 sensors (all). Cleaned and checked EGR, MAF. Cleaned throttle body. checked function cam pos sensor and TPS. Ok, the question... Why will it only start when the temps get up to 75*?

 

I have replied in your original thread. Hope it helps you out.

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