hey guys! was driving my 1993 ls400 on the highway and it cut out craaazy and cel came on so got home and checked it and got code 41 (tps signal) the connector had its clip broken so i assumed it was that and got a new connector and it still ran bad and
still didn’t drive and i kinda just left it. fast forward i wanted to get it fixed and i ended up changing the oem maf to an ebay maf i had that was extra because i think i had scanned it again and got code 31 (air flow meter signal) still didn’t fix it and it ran bad. next day i miraculously found another oem maf and put that in and cold started it and it was sitting above 1,100 rpm and that was healthy; slowly dropping as it warmed up but as soon as it warmed all the way up it dropped to around 500 and cel and other lights came back on and got codes 31, 41, and 24. i’ve had the ecu recapped from a guy but im kinda lost on whether it’s a board on the ecu that’s just damaged so i really dont know what else to do, anyone got recommendations?

 

To start, I would suggest to put your original AFM back on, as the new AFM seems to have made no difference / made it worse. I highly doubt you would get 3 bad AFMs.

It sounds to me like wiring issues. Interestingly, this owner got a code 24 from pinched spark plug wires that were arcing:
https://us.lexusownersclub.com/forum...Comment-114511

However, there are other examples like this owner's ECU was rebuilt poorly:
https://www.clublexus.com/forums/ls-...-and-31-a.html

Once you've swapped the AFM back, check the codes again - Then, diagnose the problem. Have a look at these steps for each DTC:
Code 24: https://charm.li/Lexus/1993/LS%20400...stem/DTC%2024/

Code 31: https://charm.li/Lexus/1993/LS%20400...stem/DTC%2031/

Code 41: https://charm.li/Lexus/1993/LS%20400...stem/DTC%2041/

Long story short, all of these diagnostic procedures primarily point to either a wiring or ECU problem. The AFM should also be tested, but again, I don't think it's what failed here based on your description.

 

Regarding the MAF, as is posted here, most of aftermarket ones are not quite OK.
https://www.clublexus.com/forums/ls-...l#post11990334

 

sounds good thank you so much for the information i greatly appreciate it! i’ll look into it and start doing some tests!

 

Sounds good. Also, keep in mind what Yamae mentioned about the AFM being OEM. Don't use any kind of intake cleaner on the AFM as it will destroy it