1992 Toyota 4runner V6 4wd, starts and runs strong but as soon as you put it gear and hit the gas it chokes and sputters and then stalls out. the truck will idle around 2k and rev in park just fine. I was thinking a vacuum leak or TPS but I wanted to see if anyone else had this issue and has resolved it.

 

Runs strong? Do you mean the engine idles after starting it up?

Do you have a CEL illuminated? Have you checked your vacuum lines? Tested the fuel pump? Checked ignition components? Cleaned out the throttle body? Tested the TPS and VAFM? EGR system in working order?

 

Yeah Engine Idles great with no hesitation in park. It actually idles at around 2k rpms which I think is too high but this is my first 4runner so im not sure if that's normal. There is no CEL, I just purchased it yesterday so I haven't gotten into it yet but the guy I bought it from says it just started that day. Seems like a straight up guy so I don't think he was lying. When the truck is in park and at idle I can Rev the motor just fine and there is no issue there, but as soon as I put it into drive and gas it, it chokes and stalls

 

Low fuel pressure. The pump can't keep up with engine demand when it revs.

I had EXACTLY the same symptoms. I could hear the pump running but it was noisy. Replaced the fuel pump. Problem solved.

 

But that the thing DCMatt, In Park it will idle and Rev just fine with no hesitation. But as soon as I put it in drive and hit the gas it chokes and stalls out. I will then place it in park and crank it up and it will idle and run fine... until I put it in drive and hit the gas.

 

It's still very possible it's the fuel pump. It might make enough pressure to run the engine with no load, but as soon as you put in gear it doesn't get enough energy to spin the tires. will the truck roll in idle?

Or your fuel pressure regulator

 

Marsheen, Yeah I believe it will roll a little without hitting the gas. I will be picking up the truck on Saturday. I just wanted to find out where I should look first. Like I said this is my first 4Runner.

 

I picked up the 4runner yesterday and spent this morning overlooking everything, i found evidence of a replace AFM, fuel filter and fuel pump. I think the guy replaced the stuff trying to fix the problem and just gave up. I noticed the air line diagram on the underside of the hood and found that one airline was not run the way the diagram showed. It ended up being the line for the fuel pressure regulator. And that fixed my problem

 

Fuel pump cannot maintain pressure, or you have a failed regulator. 2k is way too high an idle, needs to 800. Does it bang and knock your teeth out when you drop it into Drive?? Winging it in park means nothing, other than its running.

You have an air leak into the intake manifold somewhere, use an unlit propane torch to "gas" AROUND STUFF until it drops and that is where your leak is.

 

Yeah I found the problem earlier today, i double checked the hose diagram to make sure everything was correct. I noticed someone routed one line to the fuel pressure regulator and then to the throttle body when in fact the regulator is supposed to be routed to a hardline going towards the egr. I replaced the hose and BOOM, no more stalling and then a check engine light came on and i pulled the code for the tps which explains the high idle.

 

Good to hear it was that simple