Inabj2

Ok ever since i got the car back the car has run sluggish at low rpms, but has nice top end.

Problem: At low speeds and at low revs the car is extremely sluggish it feels like it has no power, and when just started or cold or up to an hour after starting the car is EXTREMELY Hesitant to rev. Ussually particularly beyond 3 to 4k revolutions. Some times i also encounter resistance to revolutions at lower rpms like 2k. or off idle. Sometimes i encounter EXTREME resistance and the car stays there and stagnates. at that rev, inhibiting acceleration completely. Once the 4k rev is passed however full power resumes and the car accelerates briskly to redline just like before or maybe even better. This is a problem at low speeds or accelarating from a stop. At highway speeds the hold up is barely noticeable.

What I do know: I was informed that while my car was fixed, Pemex fuel was put in my car, the cheapest variant. Pemex fuel is mexican fuel and its know to be extremely dirty, and low in octane. Then the car was driven back. Roughly half a tank of this horrid fuel was put in the car. That tank has been ran to the car and was mixed with good fuel and octane booster. Since then premium chevron 91 octane fuel has passed through a full tank once, and i just filled it with said fuel. Since then 3 bottle off octane boosters has been used. (one bottle for each time I visit the pump.) Also a fuel injector cleaner additive has been added at last fill up.

Also since my car was rear ended the piping at the rear right muffler was destroyed I cut out the bad portion out, thus currently the car runs with only one muffler on the left side of the car. Theres no engine light on at all. The only extra light on is the rear lights dont work one and yet all my rear lights work...

What could it be? remaining of the bad fuel? Maf? (then how come i get top end?) I was hoping it was just the fuel and this **** would go away. Put still persisting.

Also my starter just started to go ****ing bad, I no longer drive this car as often as I used too.

Any helpful inputs would be GREATLY appreciated.

B1TEM3

on the exhaust, where was the portion that you cut? did you weld shut the bad exhaust?

How is the idle? did it miss and smell fuel outside?
i had similar issue after i wash the engine, water got to the valey on the center of the block.
i had to remove throttle body and cleanning the spark plug on the 3rd and 4th cylinder.

Inabj2

The portion that was cut was right before the bend that leads to the right (passenger) muffler. I had to cut it out becuase the piping in that section was extremely restrictive.

Idle at start up and at cold is extremely bad, and erratic, once the engine warms up (read 30 minutes to an hour of driving) Car idles ok. There is a smell and the exhaust seems to be rather hot at beggining. Especially first 30 minutes to an hour.

Once its warmed up car just hesitates on previous mentioned rpm levels. Im using a friends slightly modded s14 as refference when I beat him, the car is fixed....

MeehSoFly

Hey!! I have the same problem. When I bought my 92 sc400 couple of months ago, it doesn't feel like
it has any power at low revs. At first I thought the car had power, since it was a v8, and I never owned a lex v8. but after driving it for a while, It feels weak for a v8. It would choke at low revs and after about 4k rpm it go. Is this normal? I usually pump 91 octane premium fuel in it since that is all we can get in oklahoma. I thought it might be the air filter was dirty and that's why it was choking at low revs, but after i checked, The filter was clean. I also put chevron techron engine fuel cleaner in the tank helped a lil but doesn't really help that much. Does anyone a solution that might help it w/ the power?? Any help would be greatly apreciated.

SupraCoup3

check your spark plugs -- that crappy fuel could have fouled them.

and while you're at it, cap, rotor, and possibly wires (if you haven't done it in the past 60k)

I did this to my GF's SC a week ago, and it made a world of differance.

JT

Inabj2

I did the cap rotor and wires myself like 10-12k ago, Im sure thats fine. Or I hope Im going check the front spark plugs... see how thats doing..

Choritsu-shi

I agree with SupraCoup3, your plugs are fouled and need to be changed. To add, you should never run octane boost when your car isn't running well enough to burn off the gasoline. That's a double foul... Stop using that crap you shouldn't even use it when your car is running good. Same as for the "injector cleaner", I don't recommend using that more than 3 times a year. You should change the engine oil and filter as well. All the fuel, octane booster and specialy the cleaner residue breaks down the motor oil and washes the oil film off the cylinders walls. This doesn't allow for a proper seal which reduces protectection and compression,which makes the engine harder to start and noisier.

Sensei

EUROJulian

Most injector cleaners are Toluene based, at least one I have acces too. Same majic component as in "Race Gas" hailed by many.

Use as much as you like, it is not doing much, (small bottle for 20 gal tank ..) but if it makes you feel better there are no problems....

Inabj2

Ok..the fuel is leaking out of the hose that connects to the fuel filter Im thinking that my fuel filter is super clogged up. Also I pulled upt my first 2 spark plugs just to revise em. Yep.. they were a lil dark and had some stuff around the edges.

Unfortunately my Lexus had to special order the filter along with other misc stuff so For now the lexus is grounded and closed in the garage. My 240sx will resume my weekly trips to phoenix until I get parts resolved. Only think I could get on the meantime were the spark plugs, and im not putting those on till I get the fuel filter replaced first.

While im at it you think I could get the TRD air filter from lexus?

Choritsu-shi

Yes; agreed Toluene helps keep fuel injecters clean, and removes gum and deposits from injecter components. But when you add it to old and/or stale gas, it loosens deposits left by previous fuels and sends them downstream - through the pump and the filter. When this residue dries, it leaves a coating of varnish that is hard to remove. I guess this would explain why Inabj2's "fuel filter is super clogged up".

If it's not doing much... then really, why use any at all? Granted not all cleaners are the same. Although not applicable to the Toyota injectors... some cleaners have harsh chemicals that can deteriorate the protective coating on the coils of the Multec (GM) type injectors and destroy them.

Sensei

Inabj2

I sourced the leak its coming from the bottom of the tank, where 2 lines come out of it, the rubber gasket that connects the tank to those 2 lines seem to have been missinstalled or is old...

Ugh doesnt seem like a easy thing to replace if I had a hydralic ramp, or maybe several large cats, I just need a way to lift the car enough to reinstall it? I gather Ill probably have to remove the tank as well.

Welp lexus is temp out of commission till that leak is resolved. Looks like such a stupid thing to go wrong too, bah damn this lack of tools thing.

Thats almost irrevelant to the problems i have with car running rough at low rpm levels, but I have already ordered the fuel filter anyways.

EUROJulian

Personaly I use cleaner continuosly on my SC. Every tank. I will be doing this for some time, I think like 10k miles of so. Car is old and need it.
Cleaner helps dissolve stuff deposided in the tank plus is a cheap protection from bad gas. It is a whole idea of the process to burn dissolved stuff in the engine.
I do not understand what do you mean "...when residue dryes".
In the situation of gummed parts there are no options. If the cleaner doesn`t work components have to be replaced.

Now, there are problems associated with fuel additives. Most importand some can be corrosive, not liquid itself but vapors. Well this days they say even milk is no good for you so like with everything use on your own risk.

Lastly, Toyota fuel filters are resistant to clogging up somehow. Basicly we do not see problems associated with those. On my SC f.e. filter is still oyginal 12 yeoa and badly stuck. It is high on my list of the things to do but I`m not going to deal with it anytime soon.

Choritsu-shi

Cool...good info to keep in mind.

I do not understand what do you mean "...when residue dryes".
... no matter how little or for how long, whenever there's exposure to air.

12 years??? that's a testament for why one should use "Geniuine Toyota Parts"

Sensei