Ok, I searched and couldn't find this before anyone points that out.

93 SC400
Just replaced all plugs and cables
Put in the DIY BFI
adjusted the throttle cable so there is no slack
cleaned the MAF, cleaned that little nipple thing at the top front of the intake
cleaned throttle body and seafoamed it via tank and air intake but not crank case
just did the Solenoid 4 mod to the ECM

so, from a dead stop, if I put my foot down the engine goes very low (sound wise) like it's flooding or something and it doesn't take off very fast. Once I get up to about 10-20MPH the engine is roaring and I am going like my pants are on fire and life is good, but off the line it just feels like it's struggling, the first 20 yards or so are less than impressive and I was hoping some of this stuff I did would improve that.

Any ideas?

 

Reset the computer?

 

have you checked your plugs? are they all firing, i had a similar problem on my old car. Turns out there was a few white spots on my plug wires from them ground on the valve cover! Possibly timing too? oh and of course on a lowered SC always check the wires that run in the driver fender well. That seems to magically fix all your gremelins...

 

I had the same issue - and still have it

I did everything you did + TC 2800 RPM the car is still suffering from a dead stop

HOWEVER, when i unplugged the AFM and i drove the car without it, it made it gain a lot of power from a dead stop, on the other hand, I had a ful ltank and I only drove 153 miles before I had it all gone

I would say it is the way these SC's are designed?? not sure, but one thing for sure, I am trying to swap it for an M3 now - Crossing fingaz

 

THANK GOD I'm not the only one with this issue, I have tried everything I can think of just short of checking the HG (when I get time that is next in line) and nothing is helping. The other issue I have is my car has to get up to 2000 RPM before the speedometer needle moves and I get a whine/whistle from a dead stop in first gear, but I'm pretty sure that is related to my differential which might be playing into the slow take off.

I have done the following

-New Plugs and wires

-New Ignition Coil

-New MAF

-Hand cleaned the TB and used Seafoam
and a few other things, but nothing is helping.

At this point I'm thinking one of the following

HG is leaking And needs to be replaced, Worn rings or both.

 

Of course the first guy has an SC4 slightly diff. animal. How about a new fuel filter, and air filter. Also read the thread on installing a new coolant temp. sensor.

 

I'm thinking that it could possibly be your ECU that is bad. Have you tried what AyDee said? disconnecting the maf and see if it runs better.

 

Just to warn you, when you disconnect the AFM, if you hit the gas all th way down, you will notice that the transmission feels like its slipping at RPM's higher than 5500 - don't be scared - It happened to me too, and everything will be back to normal when u plug the AFM back in

I am thinking if it could b the differential actually that causes these slow take offs - hm

 

it could also be EGR leaking, that would cause it to bog down at idle. check for any EGR codes stored on the computer.

 

thanks for the input guys. I did reset the ECM and it seems to be a bit better but it was always intermittent. Sometimes it would just take off like a raped ape, and other times feel like a Ford Tempo for the first 0-20MPH. No particular connecting factors thus far.

 

try checking if outside air is a factor. or if its engine temperature. If you notice that it has to deal with the engine temperature, then check out this thread:
https://www.clublexus.com/forums/per...mely-rich.html

 

I am going to replace the filter today and see if that helps, just had ALL the fluids done a bit ago too.
If that doesnt help I may just drop the $100 and get a new (used) ECU and see if that helps, even if it doesn't at worst I have a backup for when it DOES go.

 

an ECU for 100?? where from?

 

There should be a way to test the ECU, anyone?