Hello, I just bought a used sc400 with 180,000 miles... My second lexus.(first one was an is300)
I bought this SC400 for 1500 bucks.

Here is the strange part though....
I am getting a check engine light number 13. When the maf is plugged in it sputters and bucks while driving at any speed. When unplugged its smoother but still not perfect. HERE IS THE KICKER THOUGH!!! When the maf is plugged in, MY SPEEDO DOESNT WORK. When the maf is unplugged it works fine.... RPM gauge stopped working 2 days after i bought it. Ive done my research but ive never come across this speedo thing along with the maf sensor scenario. Is my crank sensor, cam sensors, wiring harness, or ECM bad? Idk

Thanks for any help yall give me.

 

I would take a look at that ECU, and I say this because I had the same exact code on mine but after the ECU rebuild the code disappeared completely and never returned... Tanin Electronix is the place to go. Bad ECU's do funny things, and the small price of getting it rebuilt is something most should do just as preventative maintenance at that age/mileage.

 

Alright ill try that. I was gunna send my climate control module and my gauge cluster there anyway. Might as well put them all in the same box. If that works then all my problems will be fixed by one company...

 

I sent my ecu to tanin auto and it checked out fine they did repair something with it and whenever I installed it back in the car it did fix the bucking issues that I was having but it still sputters a bit with the maf plugged in. With the maf out it runs fine. all of the codes are still there.what should I go to next?

 

The gauge cluster was having problems. Tanin also fixed that so the RPM gauge and the speedowork fine now

 

A bad MAF would be my next guess.

 

I see that you can just buy the plastic housing on top of the maf where the connector plugs in, and i see where you can buy the more expensive whole assembly. I dont know anything about mafs.

What should i get?

 

The plastic part is the MAF. It bolts to, and the sensor extends into, the metal tube which contains the honeycomb grid after the air filter.

 

So all i need is the maf?

 

Unless the honeycomb is damaged, which probably isn't very likely, then yeah, just the MAF should do. You can run some diagnostic tests on it before replacing, but used ones aren't very expensive and it couldn't hurt to have a spare on hand.

 

Depending on the year. it either has the square housing with the honeycomb or the newer rounded housing with just 4 fins. If the housing itself doesn't look damaged then I would just replace the sensor on top. They hardly ever go bad so if you can find a used one great, I have no idea what they cost new.

 

Double check to make sure you have the correct year ecu and its working properly, but first I would replace MAF.. I have one for sale if you cant find any.

 

How would I check to see if the ecu is correct? I sent it to tanin and they said it works fine. Half of the writing on the ecu sticker is rubbed off.

After i check that and if its ok then i will buy your maf

 

If Tanin said its fully functional then they're probably right sounds like you've ruled it out already