Engine stalls when braking or idle

[SARguy]

I have been chasing intermittent low rpm to the point of stalling on my 97 LC. 270000 on the clock. It happens only when the truck is hot and when I use the brakes coming to a stop at the bottom of an off ramp, or at the top of a hill. Never does it at a plain standstill. Reading this thread, I realized it's only happening only when brakes are applied. Never occurred to me it could be the booster. I've checked all vacuum hoses. EGR system etc. I replaced the Idle air control valve. no results. I ordered an after market booster. If that doesn't solve it, I will install it on my LX 450 because I already know that booster is toast ( when it's real cold it hisses when I apply brakes.) I will post results next week when I install the new booster.

UPDATE On my low RPM/stalling problem: I never installed the booster. While thinking through the problem I realized the one part of the vacuum systems I had not looked at was the PCV valve. Hmm? Think that almost 20 yrs and 272,000 + miles might call for a change out on the original PCV valve? I slapped in a new OEM pcv and grommet and the low idle/stalling problem is completely resolved.

 

[krahsh]

UPDATE OF OP: Ok so, I took it to Toyota dealership and they diagnosed it as a faulty Idle Speed Control Valve and torn PCV gasket. I replaced both and drove with no problems for 40 miles. And then while I was at a stop, it idled low again and stalled out. I just want to

 

[ton504]

I would be looking very close at the booster or gasket on the firewall. Seems like it could be leaking when you put some force on the pedal.

 

[krahsh]

I would be looking very close at the booster or gasket on the firewall. Seems like it could be leaking when you put some force on the pedal.

Ordered new booster and gasket. I'll update after I pick them up and installed

 

[krahsh]

installing was painful! all bruised up & cut knuckles, but the booster is installed. first test drive result is much better braking. I will drive it over the next few days and see if problem still exists. thanks for all the help

 

[krahsh]

Another update: replaced brake booster and took it to for a litte 4x4ing in some mud. Well offroading went fine until i get off of throttle and again it idles to about 300 and then stalls. So problem still exists, i'm thinking fuel delivery issue? any other suggestions? thanks

pic from today

 

[krahsh]

yet another update: replaced fuel filter & still the issue remains. now i am going to change plugs and cap and rotor and see if that fixes it. i'm running out of ideas on this.

 

[scottryana]

Have you done a real thorough vacuum leak test? What about the lines under the intake? Charcoal canister line to intake? It sure sounds like a vacuum leak to me.

 

[Landseer]

I had very similar issues on my 94, turned out the flex joint on the air intake tube was leaking. I wrapped the flex joint in duck tape and the problem stopped immediately, new intake tube cured the problem for good. Interestingly, there was essentially no visible cracking on the flex joint but it was definitely leaking.

 

[krahsh]

Best procedure for thorough leak down test?

 

[krahsh]

I have been doing extensive work my self trying to figure out the issue I have been having with engine stalling out. I have come to extent of my limited knowledge and have had to now work with Toyota trying to figure out the problem. Changing out several parts have made things better, but the problem still exists. They have now come to the conclusion that I need to replace the computer. As it is not properly controlling the idle speed control valve.

So I have put up a WTB add for a 94 fzj-80 ECM. Wanted - 1994 FZJ-80 ECM

 

[Maleficio]

Replaced my air filter today and suddenly induced loping idle and stall. Pulled the intake hose and it ripped in half. Taped it back together with silicone tape, reinstalled and now back to normal. Ordered a replacement hose.

 

[ChaseTruck]

This helped me when the '93 didn't want to idle:

1993 Fj80 Rough Idle, runs great other than that

 

[Maleficio]

I considered ordering a nice silicone hose, but recalled how difficult the big ones are to work with after installation. So damn tight! Have to use a heat gun for installation.

 

[notathomie]

I feel your pain. Just went through something similar (Search for post entitled "Stuck in the Jungle").

Not sure if your car has a fuel pump relay, but if it does, switch it out. Fuel pump relay part number (for a 1997 FZJ80 40th): 28380-66010. The local Toyota dealer charged me US$60. I also ordered one from Partsouk on Ebay for US$65.