Hello, as mentioned in the title bar, my car has been stored and not started for the past 4-5 months (due to winter/dead battery). I just changed the car battery yesterday and took it around the block and the car felt extremely sluggish. I was very disappointed. What could have gone wrong here why the car is feeling sluggish? please let me know. Thank you

 

It would help if you provided some further details on HOW the Z was stored. Was it outside/inside? Up on jackstands or left sitting on the tires? Any fuel preservative used in the gas tank? When was oil/filter last changed?

 

was stored inside garage, the most i did was left the e-brake down, it was sitting on tires no fuel preservatives oil filter was changed with last owner which is unknown.

 

How much fuel was in it?? Bad gas and oil also. I wouldve put some stabil or sea foam in that thing while being stored like that IMO. I'd try and get the fuel out and get some sea foam w new fill and see what happens. GL

 

I agree- fuel can deteriorate and why would you even start your VQ without knowing how long it's been since the last oil/filter change? Start with those two factors and let us know if the Z wakes up with fresh fuel and an oil change.

 

Could also be that the car needs to re-learn after the battery died.

 

relearn what? does your computer lose its programs when you turn it off?

ECU's don't lose anything.

I'd say its probably the same as before, you just aren't used to it.

Even if bad gas dropped it down to the low det map, its not that big of a difference.

 

Actually modern ECU's do learn, and for the first 60ish miles after losing power they are in learn mode.

 

Agreed, they will learn for a few miles after being dead. You should also check for any possible codes, even if the CEL is off. Mine had a bad knock sensor and/or sub harness for a couple weeks, but there was no CEL. It also wouldn't hurt to drop some iso-heet in the tank and check for any rodent activity in the valley as well as the air filter box.

 

I had my car in storage since Oct. I've been trying to trace down my performance issues.

All I needed to do was run some Gumout Regane through the fuel.

 

Hope you figure out. Next time prepare the car for storage. There is a sticky thread that shows you how

 

I agree with myfirstzcar comment. I was experiencing a similar problem. I didn’t have a light, but checking codes displayed a bad oxygen sensor. The car returned to normal after replacing the sensors.