Trouble starting engine after retrieving codes

[virginiakid]

I bought an '87 B2 several days ago. It had not been driven much in a good while. But it starts and runs though. I drained the little bit of fuel left in the tank today and added fresh fuel with some Seafoam. Started the engine, got it up to oper temp. Then turned off and pulled the codes. Got a 21 and 51. Both have to do with engine temp sensor (I think).

But when I tried starting the truck back up after pulling the codes it wouldnt start. it'd just turn over. finally I pushed the accelerator and it finally started. But the idle is much higher as it runs. I killed it and tried pulling codes again. But this time the truck will not kick in to the test mode. I cannot pull codes now for some reason. I tried disconnecting the battery and trying again. But it will not start now unless I floor the accelerator. And then it idles much faster than normal I(just under 1500 rpms.

I'm wondering if something happened to the Engine Control computer or some other component. Anybody have an idea?

 

[martin]

Check that you did knock off or break a vacuum hose when you were pulling the codes.