Why such a fickle mistress
 

Anyone experienced the frs/brz/86 being a rather fickle machine? Past few weeks the car's been running like shit, acceleration and shifts were sloppy and jerky and sometimes hard to start (cranks but doesn't turn over until i tap the gas). Replaced the plugs recently (took me good 5-6hrs of facking around) so I'm thinking it's the injectors. Decided to buy some fuel system cleaner to flush it out.

But after I replaced the HU yesterday, this morning it drove like a dream. Bad earth from stock radio? Plugged up injectors suddenly freed up? Thought it was bad gas but it's currently on half tank...

Did you by chance disconnect the battery when you replaced the HU and reset the ECU? If so, maybe that explains the overnight turn around.

That would've been the right way of installing a HU but I was tired after work and excited, so I just wanted to get it in. Therefore I didn't disconnect the battery, even when I was stripping and soldering to a power wire....

Have you tried the old Italian tune up?

How recently did you replace the plugs? Assuming you unhooked the battery when you did that job, the ECU was reset at that time and had to "re-learn" which does cause odd feeling throttle and whatnot.

Every once in a while mine seems to have slept poorly but never spanning days.

I know exactly what you mean. I feel like every time I drive my car it's a little different. I've only had it a month and the first half of the month I was making changes with a Tactrix cable. So it was constantly in that learning phase where it drives like crap. Now that I am leaving it alone and actually let if complete the learning phase it is more consistent. But it still seems like I will go for drives where something just seems off. Then today I go to lunch and something in the back is rattling like mad. WTH.. I have it a month and almost zero rattles then out of the blue, rattle. I bet it will mysteriously vanish when I leave the office tonight. Hahaha

I replaced the sparks probably a month ago. The car's driving beautifully now so I'll just flow with it.