I bought my son a 96 LS400 with 180,000 miles on it. Car is in fantastic condition and absolutely everything works.
The car shifts great but runs a little rough. It is drivable, but runs with a hesitation. The exhaust is solid white smoke and smells like fuel. I have replaced he plugs, plug wires, and injectors. Nothing has helped. Any suggestions?
The car cranks right up and idles fine.

 

check your power steering idle control valve and replace (or plug) it. it tends to leak and send PS fluid into the intake to get burned. see if the PS reservoir is still full.

more:
https://www.clublexus.com/forums/ls-...ystem-diy.html

 

Thank you. Smoke is definitely gone. Now for the misfire and rough acceleration. I think I need a new MAF

 

why do you think it’s the MAF? I would do a complete visual inspection and look for anything damaged or malfunctioning, rotted wires, oil leaking into the spark plug tubes or cracked vacuum hose, plugged pcv valve, that kinda stuff. Usually a misfire will generate a DTC, so scan it and see if it has anything in the history, but i would just do a full tuneup and service, chamge the fluids etc and clean the fuel injectors. It’s likely to fix your problem and prevent the future headaches also. A bad MAF will almost always have a DTC, plus they often don’t run with a malfunctioning MAF, I would suggest cleaning it with the specific cleaner as part of the time up.

 

I have replaced the plug wires, plugs, and injectors. I’ve cleaned the MAF. All plugs are firing when I pull them and turn the engine over. The only 2 codes that I get are 0110 IAT sensor and 0306 Cylinder 6 misfire. I have checked 6 numerous times and it is definitely firing. I have looked for vac leaks, but could be missing one. The engine cranked right up and idles 95% good. When you give it throttle, there is definitely a miss! Driving the car, low rpm’s it runs ok. Higher rpm’s, there is a hesitation and the car slowly accelerates.

 

It cranks up and idles fine, that might point to say 1 or 2 cylinders are the issue and not all 8 cylinders. The cylinder 6 misfire there is something to that obviously. So you replaced the injectors and you state you smell fuel from the exhaust, maybe fuel is not burning in at least one or more of the cylinders but... something is going on there with fuel smell from the exhaust, sometimes you can't see codes with fuel issues but is it running rich on say just a 1 or 2 cylinders or all of them? If its all of them it could even be an 02 sensor issue or something else causing everything to run rich. Question is are the codes pointing to that and if not why not, so it's interesting kind of sifting through the diagnostics.

 

Maybe take the plugs back out one at a time after running it and visually inspect the plugs, do they all look the same? If not, which ones look different and what do they look like?

 

some are dry and some are soaking wet with fuel. Doesn’t make sense, #6 was dry, meaning it fired

 

so if you do have proper compression in the cylinders with the spark plugs that are soaking wet, then that points to a problem with you are simply not getting spark in those particular cylinders, if you don't have proper compression in those particular cylinders that the spark plugs are wet, then that points to fundamental problem with the engine. Maybe borrow a compression tester from a parts store of whatever and test the compression in all of the cylinders

 

compression test is my next step. Gonna borrow a tool from a friend. I’ll let you know what I get. Thank you for helping me.