Stalling problem. engine starts, but stalls in gears or in park.

[Rebel_way]

Hi there!
I have a 4runner 98 v6 and my engine is acting funny.
it starts goes up to 1500rpm than drops to 300rpm and goes back 1500rpm sometimes 1200rpm. If I switch to D it drops to 800 rpm and if I switch to R also 800rpm if I switch into P it stalls instantly (doesn't meter the sequence it still stalls in P). Also it stalls when I switch to N after I start.
sometimes engine starts goes up to 1500rpm and drop down and just stalls can do that up to 5 times in a row. Also I remember it used to stall in P after driving for a while its like it stops the engine before you turn the key off.

 

[jgue467]

Have you cleaned any of the intake like the IAC and/or MAF? Any other maintenance done?

 

[DK327]

My Grand Am did this and it turned out to be dirty throttle body, cleaning it with TB cleaner resolved the issue.

 

[soupkitchen]

you might check for vacuum leaks. I had a hose on the firewall that had a crack in it and was doing the same thing. Replaced it and was good to go!

 

[Rebel_way]

Last night I pulled out TB gave it a good clean (wasn't too much dirt)
IAC valve had a good clean too...put it back together still the same
Today gave a good clean to MAF sensor and nothing. also checked coil pack resistance and ground points all is fine, spark plugs are good, and still same problem.

No codes.

 

[Rebel_way]

you might check for vacuum leaks. I had a hose on the firewall that had a crack in it and was doing the same thing. Replaced it and was good to go!

how to look for vacuum leaks?

 

[Rebel_way]

checked for vacuum leaks with carb cleaner..found nothing.

 

[Rebel_way]

code came up
P0335
Crankshaft Position Sensor A Circuit

 

[stir_fry_boy]

Looks like you will be needing a new crank sensor and while you are there a timing belt and associated components.

 

[Rebel_way]

So I found a way to pull it out its ohm readings 2.12k ohm and range should be between 1.6k to 2.7k ohms so it's good. it. was dirty I cleaned it up put it back but, doesnt look like it fixed the problem...still same rpm drops and stalls

 

[Rebel_way]

also I checked on the circuit continuity with test light and it worked fine.
tried the thing with the key in on position and was able to hear clicks from the spark plugs ( https://www.youtube.com/watch?v=LaTEPhB1_C8 ), so It doesn't look that it has to do anything with the sensor or circuitry to it. Code didnt came up 24hr later and more than 100km drive.
any ideas?

 

[Rebel_way]

so I replaced IAC valve (mechanic suggested replacemen) didn't solve a problem.
Also I have replaced O2 sensor the one after catalytic mainly because I had check engine light for it some time ago just for a second it looked like it fixed a problem, but after 3rd start engine stalled again in P/N.

 

[idlingmike]

No fuel trim adjustments are made off the rear o2 sensors, they are strictly there to verify functionality of the catalytic converters. Next I would try 1) Check fuel pressure 2) Get your hands on a wiring diagram and start checking engine grounds. 3) Do you have obd2 scanner? What do the short and long term fuel trims look like?

so I replaced IAC valve (mechanic suggested replacemen) didn't solve a problem.
Also I have replaced O2 sensor the one after catalytic mainly because I had check engine light for it some time ago just for a second it looked like it fixed a problem, but after 3rd start engine stalled again in P/N.

 

[Rebel_way]

I know the topic is old, but I kinda fixed the problem.
My aftermarket alarm system from previous owner was causing the problem.
It didnt allow me to start properly so I had to bypass starter relay to be able to start the engine. After I took the controller and wiring out and soldered one of the wires together completing the circuit without alarm involved( when alarm was installed it was closing the circuit on that wire).
Now everything starts and works the way it should no stalling problems or jumps of the RPM just sound working 4runner))
And yes, It starts with the key now without bypassing the starter relay.
Only the sad part is that my center lock doesn't work from remote coz the alarm is out obviously. And Open Doors dash light is dead too. I will try to hook up alarm in parallel and see if it is going to make my central lock work.