Hello... My '88 B2200 pick up check engine light stays on a few minutes after start up and comes on when coasting down hill ( no throttle but still in gear).
Also where is the socket to plug in the code analyzer? Thanks for your replies..

 

There is a single green 1 pin connector near the wiper motor. Jump it to ground and count the check engine light flash's 1 long flash = 10. 1 short flash = 1

 

Thanks.. I have found the little single socket. It is white.
There is a 3 pin connector nearby that has been disconnected.
Where would I find what the # means?

 

I can tell you. What's the code? There are only 16 codes.

 

How will i recognize a specific #? Like 14.. How will I know a #4?

 

4 short flash's = 4
4 long flash's = 40

 

It's showing code # 16

 

EGR position sensor.

 

How to fix??

 

If you have no vacuum leaks,it is plugged up and no wiring problems or driveability problems i would replace the EGR position sensor and clean the EGR valve.