Problems with Blazer
 

It started out as a hard to start problem last year and cannon balled to a no start condition. So what we did was changed out the ICM (ignition control modual) and it would start! But we had a new list of problems different from what was normal for the Blazer. It wanted to die at idle and would spit and sputter and backfire badly. Well, we fixed the wanting to die at idle by changing the distributor cap and rotor button. We cant figure out the rest of the problem.

Here's what all we changed: ICM, Cam Position Sensor, Distributor Cap, Rotor Button, Spider Injector, and Ignition Coil. It is setting no codes but has a idle around 880 and once it warms up it idles around 950. Sometimes when you try to start it up it pops back against the starter. Fuel trim appears to be looking for a happy medium at idle and when you push on the gas it spits, sputters, and backfires. So checking fuel trim at 1100 and 2500 is imposible because rpm drops and surges during this time. When you unplug the throttle position sensor it got a little better but it didn't get rid of it completely.