LS1Z28_98

2 weeks ago I had an episode with my 98 Z, mods are in the sig. Mind you the only tampering to any wires was to add an aftermarket tach. I was sitting at a light and the gauges, radio and trip meter went bananas. When ever the the gauges or radio would die, the car would want to. It was just little blips. That worked it self out. Took it on the expressway for a mile, ran OK. got off and the throttle hung at around 2500 like there was a vacuum leak. Got to the next light and it wanted to die, I had to rest my foot on the gas to keep it running. By the time I got home all was almost normal.

I have a Nick Williams tune on it. The RPMS are about a 100 to 150 higher than what the tune was. Also it seems to slightly search for an idle. It surges, by 300 rpm over and over, stop for a sec and start that again. Battery and Alt check out OK. Checked all the grounds I could find and they seem tight. Checked the wires to the tach and all seems legit, no chaffing or anything. I am at a total loss, and now really don't have the discretionary income to spend a fortune at a mechanic or at the tuners...(THANKS OBAMACARE). I am gonna clean the MAF tommorrow and try unplugging it to see if it rights itself.

Any possible ideas at all? Its killing me b/c the weather is nice and want to drive the SOB instead of it being dead lined.