Rough idle after changing heater core!

[alexthesween]

Changed my heater core out on my 89' 5.7L 4x4 1500. Took the air filter and housing off to get to some bolts. Had to disconnect the computer under the glove box to get to it as well. switched it out, plugged everything back in and put er back together. Now she idles really rough(especially when cold), smells like she is running really rich, and does not like shifting out of first. Vacuum issue? Ignition? Tiny unicorn living in my throttle body and poking holes in stuff with its horn? carburetion? need some input if you got any! Thanks!

 

[zora]

any chance you disconnected the vacuum line going to the fuel pressure regulator? Did you disconnect the battery before disconnecting the computer? Did you check for any blown fuses if you did not disconnect the battery? Any codes in the computer?

 

[Chuzz]

Take a good look at the plug on the computer under the glove box. If it's not 100% plugged in, that could cause problems. I'd unplug and plug it back in two or three times just to make sure. If not that, then I'd take a close look at the vacuum lines around the breather and air filter housing, like Zora suggested. There's no reason that a heater core change should change the way it was running before you started.