Odd happenings. Help Requested. Car dies, Code 31 then 24 then no code.

[Amontgomery]

I had been having a miss under hard acceleration so I changed the gap on my plugs from 31 to 28. The miss was gone. While I was at it I shimmed my wastegate about 3mm.

On my test drive I gradually allowed the engine time to heat up then punched it in a straight away from about 30. The car pulled like I expected and got up to 90 very quickly and smoothly with no miss. At the end of the straight away I came to a stop. The car idled normally. I turned and headed for home, a little low on gas. About a mile down the road the car just dies. I figure it is just out of gas and as luck would have it I was close enough to coast into a gas station and push it up to the pump. I filled up and the tank only needed 13 gallons, 5 gallons short of it capacity. I checked the codes.

At first I got a 31(MAF sensor). I checked the plug, and cleaned it off then re-plugged it in. I cleared the ECU and cranked the car. It ran but with the CEL on. I checked the codes again and got a 24(Air temp sensor). I cleared the ECU again and headed for home. As I come to my next stop the car dies again. It cranks right up without hesitation and off I go all the way to the house with no more incidents. When I get home I check the ECU and get no code. The car idles fine and runs smoothly.

What could cause this? I checked all of my connections and everything that I did and everything was back exactly the way it was supposed to go. Is this the sign of something failing or is there something that I can do to fix to prevent this from happening again?

All help is appreciated.

 

[Nick M]

You likely have a connection problem, since you have both airflow meter codes. They have a common supply voltage, so that could be it also, but a connection fits the puzzle quite well.

 

[CRE]

Looking at the TEWD, the thermistor doesn't share anything with the rest of the KVAF's circuitry. It's possible the grounds are shared at some point, but it's nothing to do with the power from VC. I'd start with checking your grounds, namely E1 and E2.

 

[suprahero]

My wife's car shuts itself off from time to time. It pisses me off, but it's never thrown a code after doing it. I think hers has something to do with the vacuum that runs to the powersteering. I don't think the engine idles up like it's suppose to when you're turning.

 

[Amontgomery]

Thank you all for your responses, I must appologize for the delay. I was taking my wife out to see the new Indianna Jones movie.

I had similar thoughts as to problems with connections. As well as something requiring vacuume being a cause, as the car only shuts off at slow speeds or under braking. I figure my wiring could use a thourough look over and many of the grounds cleaned up. I have noticed that sometimes the car will not turn when being cranked, not like the battery is down but like no power to the starter at all. After a few tries it cranks right up with no problem whatsoever.

I have both the TSRM and the Haynes manual for the Supra. Do I have the requisite wiring diagrams to find and repair problems with the grounds/connections?

Also, Many of the vacuume lines had been pulled from my engine before I ever owned the car, including the one that runs from the bottom of the accordian tube to the power steering(which has a bad leak so I am going without filling it at the moment). Is there another line dealing with braking? Should I replace the steering one?