I got my blazer running I thought I had it.right now it has a surging idle and tries to die when you its a 2.8 1988 blazer its throwing a code 34 and 42 any advice on where to start or what could be causing this

 

I reset the computer now I only get the code 42 this thing will sit and idle in park all day but when you put it in gear and take off when come up to a stop.sign it will die every time

 

Either your timing is off a little bit ( turn distributor to advance a bit ) or you have a vacuum leak. If turning the distributor and checking timing does not solve your issue, then mix up a spray bottle of soapy water and check for a vacuum leak.

 

i will check timing tomorrow thanks for the help

 

GM OBD1 with Code 42 | Extreme Check Engine Light Codes