RadRob

So Ive had the car for a few months now and it has been doing this since the day I bought it. Its nothing serious to the point where the car is undriveable, in fact, its very slight. When I step into it a little harder than normal when getting on the freeway to get up to speed, you can feel it. It feels like the car sort of hesitates throughout the RPM band, and sometimes feels like the car has very little power. It does it even more so when the AC is on. I checked the transmission fluid today because that was my first thought, and the fluid looks brand new still. The guy I bought it from said he had just spent a little over 2k in maintenance weeks before I bought the car. I know for a fact that the timing belt was done. as they placed a new sticker with the mileage on the radiator core support. Was done about 7k miles ago. So I'm just assuming that while that was done, he had the transmission serviced as well. I smelled the fluid, and it does not smell burnt at all. Based on that, I went ahead and eliminated that out of the equation. I didn't have time to check the plugs since it was getting dark, but I am assuming those were done as well. Doesn't mean I'm not going to check them anyways though. So basically I come to you guys for some suggestions that I can look into. Ever since my battery issue I posted about a few weeks ago, the car has been running great. This hesitation issue isn't even a big deal, just something I want to resolve. I'm putting some TLC into this car to keep her on the road for a very long time. The car does have 191k miles on it, and its a '93. Once I get the little things like this taken care of, I will move onto the things that need serious attention, like the interior. haha. Anyways, any suggestions you guys might have are greatly appreciated!

RadRob

Also, instead of making a new thread, Ill post here as well. My A/C compressor is making a ton of noise. I checked it out today, and it looks like the pulley is wobbling on there. The A/C works great, so I don't need to replace it. Do you guys know if I can just get a pulley bearing for it? Or even just a whole new pulley?

PerpLexusd

what I bet your hesitation problem is, is when they replaced your water pump they probably didn't get the timing exactly right when they put the timing belt back on. these cars are super finicky about that, when I replaced my water pump I had to tear it all down and put it back together like 5 times before i got the timing right. it started first hesitating really bad, i took it apart and put the belt back on then it would hesitate slightly like how you say yours is doing, did it again almost no hesitation but check engine light came on, did it again no hesitation but CEL on, did it again and finally it was all perfect...needless to say I can replace a water pump in like an hour now. So maybe getting your timing checked by a Certified Lexus mechanic may be an option

RadRob

I will definitely look into that. The only thing that has me confused is that it doesn't do it all the time, but sometimes when it does it its really noticeable.

avalon42

iTrader: (1)

When was the last time the spark plug wires were changed? If they were changed recently, find out if they used OEM wires.

After pulling my hair and car apart, I found that OEM wires made back in 2002 pulled from a JUNKYARD brought the LS400 back to silky smooth mad-speed, while aftermarket junk wires made in 2010 fell apart after 1 1/2 years.

RadRob

Im actually not too sure when they were replaced. Im thinking I should just change the plugs and wires anyways since its not that expensive and can eliminate that out of the equation.

RadRob

Ok, so today I went to the DMV to get my new tags, only to find out since I am the new owner, I have to smog the car. I had a bad feeling from the beginning this was going to be an issue. So I decided to take it by a test only center to see if it passed. If it did, then I was in good shape. If I didn't, I wouldn't have to pay, but obviously I would have to track down the problem. So unfortunately it failed. It passed everything except for part of the test where they drive the car at 15mph and 25mph. I forgot off the top of my head the exact name, but the guy told me it could be because of a tune up issue, and that it didn't seem like it was a major problem.

So I decided to take it home and on the way picked up new plugs and wires. While doing this, I found that my air filter was DISGUSTING. I snapped a pic and Ill post it later. There are like 10 hornets stuck in it. haha. Anyways, obviously I went and got a new air filter.

So now I have new plugs, new wires, and a new filter. Car still seems to be running the same, but Im curious if it will pass now. Any other ideas?

PureDrifter

iTrader: (10)

its pretty common knowledge that the seller is responsible for smogging the car in california. What you should post is the actual results and what part of the test your car failed (ie-HC or NO or w/e at what speed/rpm)

RadRob

Yeah, I just haven't really been in this situation before since this is only the 1st car Ive purchased that wasn't new. I know now though.

Ill try to upload the printout later on tonight.

RadRob

Alright, so I spent some time today doing some research into things I should check and possibly replace that may have caused my car to fail the smog test. So as mentioned, I replaced the plugs yesterday. In doing so I found out my filter was incredibly dirty and clogged with all kinds of debris. Below is a picture of what I took out. Obviously, its been replaced.



So with the plugs and new air filter out of the way, I drove it to work and back. Didn't notice any change in the way the car ran however. So today on my way home, I picked up a new PCV valve and grommet, a can of Seafoam, and a new fuel filter. Below is a picture of the old PCV vs. the new. As you'll see on the test printout, my PCV did not fail, but you can see how disgusting it was. Being that the PCV allows gases to escape, although it didn't fail, it probably isn't operating 100%. So I changed it.



After I did that, I pulled the vacuum line off the booster and sucked in the Seafoam, and put the remainder of the bottle in the gas tank with about a half tank left. I let it sit for about 20 minutes and fired it up. An insane amount of smoke came out and I let it run until it stopped smoking. I am going to wait until my tank is empty so all the Seafoam is out of it, and then I will install the new fuel filter. The point of Seafoam is to help clean out the contaminates out of the fuel line/injectors when placed in the fuel tank. Obviously some of those contaminates are going to end up in the filter. That, mixed in with the fact that who knows when the last time the fuel filter was changed, if ever, I figured now is a better time than ever to change it.

So below is a picture of the printout I was given of the test. Highlighted is the reason for failure. You can see at 15mph, my hydrocarbon levels are quite a bit above the max allowed. At 25mph, my hydrocarbon levels barely exceeded the maximum allowed. Hopefully with these tune-ups I have performed, my car will pass. If not, I have eliminated quite a few possibilities at least. Also, this will give us some numbers as to how well the Seafoam works. Obviously the numbers may be skewed by the other changes I have made, but we will see. I may even do an oil change before taking it back down on Saturday too.




Thanks again dudes for all the advice and help along the way. These forums are great!

RadRob

Sorry for the ridiculously sized images, I don't know how to make them smaller. hahah

PureDrifter

iTrader: (10)

check all the spark plugs, wires, and ignitors. caps and rotors are a good idea too. high HC is usually a spark/timing issue from what i've seen.

avalon42

iTrader: (1)

Oh, I wanted to tell you that also your battery/alternator may be on its way out, go to Autozone and make sure they use that testing module, not a multimeter as I encountered at one of their stores. You can call ahead of time and make sure they have the module, best of all, it's free. Double check that.

I hope to God that you forked over the cash and bought OEM wires, none of that aftermarket crap. Keep your original wires, all of them, just in case. I hope you didn't toss them. An OEM wire set I found in a junkyard dated 2002 work infinitely better than this aftermarket wire set I bought in 2010. I would bet my original wires from 1991 would have worked better than the aftermarket crap as well.

RadRob

I totally forgot to check the cap and rotors. Ill check those tomorrow. Plugs and wires are now brand new.

Well they are aftermarket wires, but I checked the resistance using a multimeter and they are WELL below the manufacture suggestion for max resistance, so I don't think it will be an issue.

As for the battery and alternator, I had the alternator checked and its good. The battery was the very first thing I replaced on the car once I got it. The battery is now about 4 weeks old. haha


I'm going to check the cap and rotors tomorrow, but I'm wondering if some of the hesitation I'm feeling is maybe a slightly clogged fuel filter, we shall see. It could also just be that the transmission is slowly on its way out. As for the smog, Ill check the cap and rotors before I take it back in.

RadRob

So with all the tuneups done to the car, I took it back down tonight to have the car smogged. It failed yet again, and actually barely noticed any change. At 15mph, the HC level is at 137, but at 25mph went up to 40.

I'm at a loss as where to go from here. I really don't want to have to take it to a shop to have a mechanic look at it, but I don't have much free time to do it myself. Anyone else have some other ideas I can look into?