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I have a '93 SC400 with 189xxx miles, and I started to notice a week ago that it sounded like the car was missing, so I imagined it was probably my sparkplugs or wires.

A friend of mine that owns an SC already did it on his, so he decided it'd be easier if he did it, since he already has.

Changed out the plugs and all, bolted it all back up and now it's worse than before.

It's shaking a lot at idle, still sounds like it's missing.

When driving, it's a LOT worse than before, almost have to floor it to get to normal driving speed, it's popping, shaking, smoking, etc;...

So my question is, what in gods name could be the problem?...

Would a vacuum hose or something be the culprit?

He said my MAF was fine too..

It sucks, because now I can't drive it.. I might take a video later on when I get my videocamera back to show how it's acting up.

Any ideas?.. It's throwing a code now, but it's OBD1, so I have to wait until I get my friends OBD1 reader and that might be a while.

LEXZILLA

iTrader: (1)

Check Your Coil Packs If Its A Sc400 Your Car Has Two Of Them
One Of Mine Went Bad And My Car Sounded Like A Motorboat

Fireblaze

I have an SC300, and I changed out the sparkplugs and wires but it was still misfiring. Found a vacuum hose that was loose, and then it stopped bogging once that was repaired.

MT Photo

hmphh..

I hope it's a vacuum hose, but why would it be spitting and firing like it is?

It's not JUST bogging, it sounds like a rifle range and it seems to get really hot quick.

LEXZILLA

iTrader: (1)

Say Bruh I'd Check Dem Coil Packs First It's The Cheapest Way To Go

shammyhp23

i know what you should do


run it till the wheels fall off(until it dies)
but a supra motor and tranny

sc250tt

What ?....As for the op its your coilpacks.the coilpacks on the 1uzfe dies and starts fouling out the plugs .thats why its been getting worse .Hopefully you did not kill the cats yet.

Ali SC3

iTrader: (10)

my brothers SC400 had the coilpack problem.

unplug each of them and if it doesnt get worse... BINGO!!

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Update.

Replaced coilpack, fixed some criss-crossed wires, NOW the problem is back, just less so.

It more or less idles fine, but still hiccups every now and again, probably once every 15 seconds or so.

However, under load, it's RIDICULOUS.

Still the same, pedal almost has to be to the floor to move anywhere, and it sounds like it's missing like crazy.

So

Cliffs:

Idles better, still crappy.
Now under load it's uber crappy.
Replaced coilpack and sparkplugs already.

MT Photo

I'm thinking it might be fuel issues now..

Ordered a new fuel filter.

HellFish

iTrader: (5)

did you figure out the code? you dont need an OBD1 reader. jus short the Te1 and e1 terminals with a paper clip and the check engine light will flash what the code is. long blinks are the first digit and the shorter blinks are the second digit. for example

------ ------ --- --- would be 22. good luck.

1siksc

iTrader: (8)

what kind of spark plugs are you using, you only want to use the regular gapable plugs.

Ken2012

I posted a similar problem, not as extreme, with my SC400 yesterday. I replaced the spark plugs and wires with NGK; didn't replace coils yet. If not spark, maybe fuel, i.e., fuel pump, or air, O2 sensors (4) as previously mentioned. Could this be the fuel pump though?

1JZPWRD

iTrader: (59)

Check all of these....

Check then recheck..

MAF
IACV
TPS
all four 02 sensors
plugs
wires
caps
rotors
coils
then check the timing
bad ecu

the first thing I would do is the fuel ecu mod, its cheap, fast, and could immediately fix your issues....

IRONMANSC2

I just started having the same problem 2days ago, im hoping it would be vacume lines or coil pack now as far as vacume lines theres some that go to the bottom of the motor, is there a way to check or feel that