i just put a new wiring harness in an 85 turbo and it ran great for two weeks. like new almost. i sold it to a neighbor kid for high school commutes. about two weeks after the kid bought it, it suddenly wanted to die all the time while driving. he parked it. a mechanic looked at it and said it wasn't getting any pressure out the tail pipe, and so they cut out the cat. it still is running the same. it will have a hard start, but once running it will run pretty good. if i drive it, it will drive fine until it hits second gear, and then it dies. it will start again, hard, and if i nurse it real careful, it won't die again. while it is in park idling, if i manually rev it up under the hood, it runs fine unless i rev it all the way up. then on the wind down, it will die. the mechanic said he thinks its an electrical problem.

does it sound like maybe one of the connections came loose from my harness install? or maybe something else? has anyone experienced a similar problem?