computer codes

[Honda tech]

Im working on a 88 gmc truck with a 5.7 it failed smog, has engine light on and has a slight missfire at idle. I hooked up the snap on computer and another code reader to it and they both will not communicate with the computer. I have recently replaced the cap, rotor, plugs, wires, egr valve, IAC valve and one injector. When the truck is in park and you mash the throttle it stumbles and has a slight miss. It passed smog at 2500 rpm but failed at idle the co was at 5.3% normal is below 1.2 %. Hc is at 157 at idle. please help. Sometimes the engine light flashes fast and sometimes it stays steady

[90GMCZ71]

Im working on a 88 gmc truck with a 5.7 it failed smog, has engine light on and has a slight missfire at idle. I hooked up the snap on computer and another code reader to it and they both will not communicate with the computer. I have recently replaced the cap, rotor, plugs, wires, egr valve, IAC valve and one injector. When the truck is in park and you mash the throttle it stumbles and has a slight miss. It passed smog at 2500 rpm but failed at idle the co was at 5.3% normal is below 1.2 %. Hc is at 157 at idle. please help. Sometimes the engine light flashes fast and sometimes it stays steady

 

<{POST_SNAPBACK}>

 

 

 

Did you try to jumper A and B pins? See http://www.troublecodes.net/GM

 

//90GMCZ71

[Honda tech]

Im working on a 88 gmc truck with a 5.7 it failed smog, has engine light on and has a slight missfire at idle. I hooked up the snap on computer and another code reader to it and they both will not communicate with the computer. I have recently replaced the cap, rotor, plugs, wires, egr valve, IAC valve and one injector. When the truck is in park and you mash the throttle it stumbles and has a slight miss. It passed smog at 2500 rpm but failed at idle the co was at 5.3% normal is below 1.2 %. Hc is at 157 at idle. please help. Sometimes the engine light flashes fast and sometimes it stays steady

 

<{POST_SNAPBACK}>

 

 

 

Did you try to jumper A and B pins? See http://www.troublecodes.net/GM

 

//90GMCZ71

 

<{POST_SNAPBACK}>

 

 

 

 

 

No not yet thanks.