93 Sc400 Running Rough

[TXJoe]

Most of you will say I've been lucky and some might say, "what do you expect". All I can say is I'm a frugal, careful, auto owner and I don't like to waste money... All that being said, here's the problem.

1993 SC400, 121,000 miles, never had a tune up. I got the regular oil changes and new tires, etc, the usual stuff and it ran perfectly all these year... my hat is off to Lexus... excellent car. ;)

Today I got in my car, turned the key and immediately noticed a shudder... <_< the engine didn't sound right; it had a roughness to it. I drove it and was reminded of the days of the big cam, big carb, cars in the 60's, it had that lumb-lumb-lumb sound and feel (I'm not a mechanic) anyway, certainly not the way a Lexus sounds. It doesn't die or bog down, it runs fair but rough. :(

After you guys are done laughing at me , Can ya give me some pointers? No I don't want to take it to a dealer ... unless I have to.

Thanks,

Joe

[AWJ]

Perhaps you have lost a cylinder or two. You never had a tune up? You need to get your water pump, serpentine belt, spark plugs, fuel filter, pcv, distributor cap and rotor button and possibly wires on and on. If you haven't taken the time to do these things or had a mechanic do them - you really are asking for trouble. I can't say for sure without seeing it but I suspect you are not hitting on all 8.

[steviej]

are you frugal or just cheap?

my dad says he is frugal but he will pinch a penny so hard Lincoln will !Removed!. I call that cheap.

As for the car:

start with the cheap stuff (most is DIY)

Definately do this:

1. replace air filter

2. run a few tank fulls of gas with Chevron fuel injector cleaner (w/Techron)...don't use an off name brand. Or better yet, have a professional FI cleaning (~$75-90 US)

3. Replace the plugs. regardless of what the adds tell you, 121,000 is way too much for plugs. If you don't replace them, at least check and regap them.

4. if you have a replaceable fuel filter......replace it.

5. replace the PCV valve. a $5.00 item can make the world of difference.

6. If the 93 SC has a distributor then points and rotor is a must. I would think a 93 has elec. ignition with coil packs but I don't know the SC as well as my ES.

These are the 5 basics, in additon to what you have already done (oil and filter).

Just out of curiosity, with no tune up in 121k miles, what is your current gas mileage?

steviej

[brentg]

Stevei

I have a question for you. My ls400 just started running rough last week ever since My buddy changed the timing belt, we are extreemly sure the timing marks and the belt all ligned up even after the crank pulley went back on. the engine misses at 2800 rpm and above. My buddy says that the miss feel like a distributer/ignition miss. Like we disturbed something in the dist/rotor/plugwires etc. The check engine light is on and the traction control light is blinking constantly.

Do you have any suggestions??

Brent

[brentg]

I also forget to add the car has 135,000 mi never replaced the wires/rotor or dist. cap or pvc valve.

Brent

[dcfish]

:( injectors?????????????????????????????????????????????????????????