Alright,sooo I recently bought my 92 SC400,did a complete tune up when I bought it a month ago & it ran great!! But I recently let it set up for 3 days,when I tried starting it,its idle is poor(200-400rpm max),hesitates to drive normally,but when its pushed over 3,000rpm,it runs completely normal. Im new to working with the 1UZ & have no idea what this issue is. If anyone knows,please lmk,thanks!!!

 

unplug the maf and see what happens. than check 12v fuel ecu mod

 

Not trying to hijack your thread but I am experiencing the same problem. I have had MAF problems on other cars (not Lexus) and it is acting just like they did. However those cars would throw a codr and the SC 400 hasn't thrown a code.

Two questions for iriebmx. What is suppose to happen when you disconnect the MAP and second where is the 12v fuel ecu mod?

 

I have unplugged the MAF,car shuts off & the 12v mod made no difference either.

 

Alright,I've been reading around on the forums & I'm starting to believe it might be the throttle pedal position sensor. Where is it located & how do I check to see if it is defective??

 

There is a thread on here that is something like, "Definitive guide to .......... " Type this in and you should find it. Very informative on the 400. The TPS is located on the intake manifold, next to the TRAC control sensor, if it does have it. Its flat and mounted on its side. You loosen the 2 small screws that strips very easy and you adjust it while it is running. The thread will give you the specific range and so on. It is also spring loaded...

 

is it throwing any codes?

 

Alright,definitely have to check out the thread & TPS. & I don't have a scanner for it. I know some OBD1 cars have a light on the ECU that flashes out code #'s. Does the SC have this?

 

Yes tap te1 and e1 on the diagnostic box turn key to on position count flashes each time a code number is finished the light will go off for 3 seconds then show the next number code

 

Yes, check the TPS out. $80 part.

 

Alright,I was going to check my codes via check engine light,but it went out on me when I was about to do it. I changed the bulb out & still doesn't light up. Is it shorting out possibly?? Really need to get this car running straight since its my daily. & I'm picking up the TPS sensor this weekend.