Engine Problems w '93 ls400

Having difficulty on this '93 I just acquired. Can't seem to get it to keep the rpm's up when depressing the accelerator hard.
 
Idles fine. Slowly raise the rpm's by pressing the pedal gradually, it doesn't cut out until about 5K. If you just mash it, it cuts out about 2.5-3K.
 
What gives? I have heard the TPS. Tried playing with it. Made some things smoother, but doesn't solve acceleration problems.
 
ANY knowledgable help appreciated.

spend 100 bucks and take it to the dealership and have the diagnostics ran on it. i will save you a lot of guessing.

Not that any of my recommendations will solve your power problem but consider them:

What kind of gas is being used?
Maintenance schedule current?
Tune up (plugs, cables, etc.)?
Compression testing?
Leaks?
Oil changes?
Org engine or after mkt?
Throttle cable?
Are all cylinders firing? (possibly not)

G'l and keep us in the loop..

Just did tune up, changed fuel filter n idles fine. Only problematic when you mash the accelerator agressively.

im tell you man, save yourself the headache and get the diag.

Sounds like maybe a pressure problem:
 Fuel pressure (check the injectors) or problem with fuel filter (causing intermittant fuel restiction to the engine upon heavy acceleration).:shrug:

problem seems to be electronic. fuel getting there. pressure good. no leaks, no vacuum leaks. 
 
VERY FRUSTRATING!
 
Feel like just swapping the motor out of the '91 in there!
 
Could it be computer? Can I swap the '91 ECU in there to compare?
Nevermind. Not the same.

MAF?

Get the diag if you got the extra cash.

[quote=JP-LS400;190071]im tell you man, save yourself the headache and get the diag.[/quote]
 
LOL! U may be telling me " i told u so" by the end of this...

yup, take it to ur nearest dealer or whomever to get it diag..... it can be lots of things that can cause that problem and drivability diaganois isnt that easy..

I think I will just get the diag done...

that's the best way to go!:biggthumpup:

Sounds like the MAFS. 

Do you have a CEL? If so, you can jump a plug and get the code to figure out whats wrong. I miss obd1. so simple.

Need an ecu...f*&%$#!
 
anyone know where I can get 1? 1993, non traction control.

Ebay, or a Jyard.

no voltage to tps from ecu.
 
found 1 in NC for $175!  so 2 more days.

is that from the dealer or using a DVOM on the TPS?

from tps. awaiting replacement ecu...

MAF! or AFM? either or

New ecu solved the problems on the '93!!
 
Tough find. Diag worth the effort, and best of all...FREE!!! And ecu was only $175 shipped!
 
So, now I decided to do both the '91 AND the '93. Both run great. Now to start the body work on both.
 
Pics soon.