so my 1990 4runner i have drove half a dozen times (just bought) had a front main leak so i was running so of that oil stop leak stuff threw it and the idle slowly started goin lower and lower while running till it was around 300rpm so i adjusted the throttle cable to 900rpm and it went down again! so after some thought i ran some injector cleaner threw it and got no help. so then i took of the gas cap and it went up to around 2500 so i figured that was it and re adjusted the idle to 900 and took it around the block opened it up to 4000rpm for a minute and when i took of the throttle it died again!so now it will start when i hold the gas down but dies when i let it off.. any ideas i heard it could be fuel pump from a friend and also read it may be MAF or idle speed control valve? or could it be my timing belt my mechanic adjusted the timing on the distributor the other day and it hasn't been drove much since then. any help would be much appreciated thank you!

 

sounds like u first ran the stop leak and it could of plugged something, adjusting the cable wont keep your idle right, and not sure why when u took off the gas cap it went up that much.

 

You could try the fuel pump test jumper:
- http://www.4crawler.com/4x4/CheapTri...shtml#FuelPump

If that helps, it may be the Air Flow Meter (which is what normally keeps the fuel pump running), check it and see:
- http://www.4crawler.com/4x4/CheapTricks/AFM/index.shtml

 

Hey Testement-
Based on the description you gave, it sure sounds like the gas cap is involved. So, if you remove the gas gap right now, it will run "normal"? What else was done under the hood or to the gas tank lines just before the problem was noticed?

Something else that would be good to know....was this rig in storage and maybe parked for a year with the old gas in the tank?

 

thanks for your input guys i went out this morning a once it had cooled down it started up fine... thats wierd im goin to let it sit for a while running and see if the problem happens again pretty sure it will once it warms up ill get back to u guys in a few and let u know. yes zuk the plenum was recently pulled due to a gas leak on the passenger side fuel rail. it looks like it had a head job done recently and one of the little copper gaskets was missing on the fuel rail cusing it to spray fuel and it was replaced. i dont know if it sat for a long time when i bought it the guy said it was a daily driver. thanks 4crawler ill check those i forgot to mention its a v6 too.