I am new here. hello all. 88 4runner 22re fuel injected. a week or so ago started having trouble with idle revving up and returning to normal(cyclical) this happened only when my foot was on the brake . I rotated the tps a little, tweaked the idle adjustment a little.. ran fine for a few weeks. then the other nite it would start up fine then die in a few seconds. adjusting the TPS and idle setting screw didnt help this time. being heavy with the throttle not only doesnt help, it seems to make it die faster. i am thinking maybe vacuum, but cant keep it running long enough to try the vacuum tests i have found on this great forum. did some research today and got the codes. as best as i can tell they are:

24 - intake air temp sensor(THA)signal

31 - air flow meter signal

51 - switch condition signal

the thing is i have no idea what this info means or what to do with it...

any suggestions? ideas?

thanks in advance

tim

 

also,
anybody got a good used air flow sensor they want to sell.
tim

 

the first codes- 24 and 31 are related to the AFM (air-flow meter), so check the connection to the AFM for any corrosion or moisture

the other code- 51 means that either the a/c was on, or the TPS was not signalling IDL to the ECU when you inserted the jumper to pull the codes. There's another condition that can cause the code but I can't remember at the moment what it is... I think it has something to do with clutch / park-neutral switch but I'm drawing a blank.

Getting the 51 after you tweaked the TPS makes sense, so set it back to where it was.

If the idle speed changes when you step on the brakes, most likely there's an issue with the brake servo (booster) leaking, allowing air into the intake.

 

and clear your codes by disconnecting the EFI fuse or the battery for a few minutes after you do any work to make sure any future codes you get are recent codes.

 

You should look for a post on adjusting your TPS , it needs to be adjusted properly. Also the reason for the up and down idle with your foot on the brake is probably because the idle is too high. Toyota computers automatically shut down the injectors when you hit the brakes until it drops to about 1000 or so rpm. The other codes indicate an air flow meter problem. If you need one I have a couple of good used ones cheap, Let me know. Check you connection to the air flow meter, make sure it is clean and dry.

 

yup... forgot about that one, Toyota Pete. Good catch.
In 2wd, above a certain RPM, applying the brakes causes the ECU to cut the injectors in order to help with engine braking.

 

toyota pete,
i will look tomorrow locally, but if i have no luck i would love to buy one.
tim

 

here's a write-up about the tps:
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

 

I have the exact problem. My idle is at 1500rpm warm. Only bounces up and down when my foot is on the gas (only when hot). I have not had time to set my tps yet and have been thinking the tps is my problem for a while now. Is the tps faulty or just needs adjustment. Also i was told it could be a possible vacuum leak.

 

anybody got any good links for testing the air flow meter?

 

thanks yotarunna