Sluggish LS1, WHY!!!!

**Chicago TDP** · 08-16-2007, 02:33 PM

I just picked up a orginal owner 2000 LS1 Z28 loaded with a 6 speed. The car has 114K on it and has Mobil 1 Syn oil since 10k.

The car passed emissions last year. Seems to run nice, I did a compression on 5 cylinder and am at 170 psi +/- 5. It seems to be sluggish though. I changed the 5 of 8 plugs that I could get to and changed the fuel filter and air cleaner.

The car will not even break the tires loose with the ASR off. Cant chirp 2nd gear. What could I look for that would make this car so slow? Cats? Muffler? Car sounds good and all. Any experience here, I am carb guy and not use to this. Thanks

**2MuchFun** · 08-16-2007, 03:48 PM

plugged cat(s) would def. make it sluggish......get headers and off road ypipe, that will solve the problem!!

**SeVeReDiStOrTiOn** · 08-16-2007, 04:08 PM

Change all the plugs...it's time consuming and a PITA the first time but it has to be done. There's a install walk-through at this link... http://www.installuniversity.com/ins...sity/index.htm

What size and kind of tires are on?

Try doing a force relearn on the fuel trims by disconnecting the battery...put the key to the run position (discharges stored energy) and then take the key out and let it sit for 5 minutes. It'll take about 40 minutes of various driving for the fuel trims to mature.

As far as the cats go to autozone and use their scanner...check for any stored codes like p0420 p0430. Your miles might be too high but GM did extend their cat warranty to 100k+ miles....the letter I recieved from them said up to 100k but someone else on here said 120k so

**2kz** · 08-17-2007, 06:33 PM

I have a 2000 Z that's the same way, except mine only has 30k miles. When I first bought it, it would lite em up at will and always chirped second. Now nothing.

I do have Continentals now instead of the original Eagle RSAs, but I can't imagine that they are that much better tire.

Just thought of this. Was your car stored every winter? Mine's stored for 5 months a year. Wonder if the injectors could be clogging up?

I'm gonna try that battery disconnecting thing.

Let me know if you figure out anything. Definately frustrating!

**drummer52910** · 08-17-2007, 10:04 PM

I remember when one of my cats went bad on my trans am the car would run sluggish. I figured out if i unplugged the battery for an hour or two it would run normally until the light came back on. Had to do this till gm replaced the cat under warranty

**ultra_badass** · 08-17-2007, 11:18 PM

i did get one of my cats replaced by gm all warranty it is a 120,000 mile just to let you all know

**NHRAMAN** · 08-18-2007, 12:59 PM

Originally Posted by ultra_badass

i did get one of my cats replaced by gm all warranty it is a 120,000 mile just to let you all know

should have just went and bought some hiflow Magnaflows or something...stockers are REALLY BAD for Flow.

**ultra_badass** · 08-18-2007, 03:13 PM

yeah i know but it was free and im kinda strapped for money so free worked at the time

**Chicago TDP** · 08-18-2007, 03:21 PM

I am gonna put it up on the lift and take the cats off and just put some pipe in there and then go pound on it.

**ultra_badass** · 08-18-2007, 03:23 PM

thats is one way to do it

**edbird** · 08-19-2007, 03:46 AM

I read a thread recently about what a HUGE difference it made to their car when they changed the fuel filter.It gets clogged a little at a time,might try it.
If it was a missfire from a plug or wire,wouldn't it throw a code?I'm not sure on this? But if the previous owner ignored changing the "hard plugs" just as you did I would start there before I pulled cats and I would also change fuel filter!

**edbird** · 08-19-2007, 03:47 AM

Oops,I see you changed the fuel filter so ignore that,sorry!

**SSTODD** · 08-20-2007, 07:29 AM

PCV and your throttle body are probably full of oil with that many miles. swap the pcv and pull the throttle body and clean it and the intake as far as you can reach and then run a cleaner thru the system like GM top end cleaner or seafoam.