I have a 2000 blazer that had a engine change. I finally got it to crank up and run. Now when I drive it for about 4 miles it runs perfect. After that it starts jerking like and trying to stall the engine. The transfer case has a wiring plug not connected. I was told that the transfer case was trying to kick in. Can that happen? It causes a loud clanging sound and the engine tries to stall. Any help would be appreciated. Thanks in advance for your time.

 

I can't see how leaving the electrical connector disconnected would cause the 4WD to engage by itself. And I can't think of any way that would make the engine stall. Is the check engine light on?

 

Light is on. I have replaced crank and cam sensor, cap and rotor, plugs, wires, distributor. Motor was losing water but that stopped. Codes are P0118, P0452, P0507, P0102. Thanks for answering so quickly

 

P0118 - Coolant temp sensor circuit high
P0452 - Evap pressure sensor
P0507 - Idle air control RPM high
P0102 - MAF circuit low

Of all of those, I think the MAF problem would be the most likely to cause stalling, though the coolant temp could also cause it to run badly. The P0507 could possibly be caused by a vacuum leak, which might also throw the MAF reading off. Do you have a scanner that shows live data, or just a code reader?

 

Live data. I just don't know how to read it
or what i am looking for

 

The first things you want to check are the readings for coolant temperature (cold and warmed up), MAF at idle and at WOT under load, and IAC reading at idle. Also idle RPM. If you can give us those, we might be able to help. The EVAP pressure sensor should be irrelevant.