Hi guys. Thought I'd come here for help first.
So I've purchased a 1998 GS400. It has about 90k miles on it. Does not burn a drop of oil. Idles smooth. Bone stock.
Here's the problem. The car seems quite sluggish and slow.
I've timed 0-60 runs with power braking at various RPMs, after resetting the ECU, etc. and the best I could ever pull was about a 7.1. Typical is lowish 7.3s (60ft's about 2.6 seconds). To me this seems unacceptable since new the car should should pretty close to a sub 6 second. Even 6.2-3 I'd be fine with, but I'm averaging a FULL second slower than that.
My g-tech dyno (actually in my iphone, but reasonable accurate) puts the horsepower at around 180whp using a 4000lbs calculation.
I already checked the ODB reader hoping to find a code (thought the car was running in a safety map/sort of like limp mode. Other cars do this if the knock sensor and or o2 sensors are bad). Unfortunately no codes were thrown :(. Though i guess that is good. haha.
I'm guessing the car just needs a decent tune up.
Can anyone think of a good place to start?
I'm leaning towards,
Spark plugs
Clean MAF sensor
New Air filter
Any other issues with these cars that can affect their performance? I'm fairly confident the compression is good. Perhaps maybe a bad VVT valve? Is there a TPS on these? It almost seems to run more responsive/powerful at 1/2-3/4 throttle. Going WOT isn't working.
If these clean-ups don't do much, i suppose my next step would be to look at purchasing a decent obd datalogger to see what's going on ignition and fuel wise. Perhaps also hook up my wideband o2 and or do a dyno run to see what it's putting down.
This was my first lexus purchase and I know the car is capable of more. Any thoughts would be appreciated!
