ilikai

Hello here is my problem. Car was driving fine. Transmission and engine seemed very strong. One morning I went for a drive and all of a sudden the truck would not rev past 2000prm. When it would hit 2000 it would then drop down to around 1500 rpm and surge back up to 2000rpm, then again when it hit 2000 it would drop down to 15000 rpm, and it would keep doing this as long as my foot was on the gas pedal. I pulled over and it continued to do this in Park, Neutral, Drive, and L and 2. Turned off the car and turned it back on. Still happened. Drove it home like that because I wasn't far. A couple days later I opened the hood and manually opened the throttle to around 5000rpm. At that point it did not surge. Took it for a drive and it rode fine. Until yesterday again the same thing happened where I was not able to go past 2000 rpm. Please help me if you can, the truck is driving fine once again but I know its gonna happen again. Any ideas willl be taken under considereation. Thank YOu

1993 toyota 4runner 4x4 3.0 3vze, a340H,

There are far greater minds than mine on here, but I'd start with checking for vacuum leaks.

Have you checked for codes?

Agreed with Offroadnutz… could be your Tps, fuel pump going bad or a number of other things, pull the codes and go from there.

I'm experiencing the exact same issue in a 94. If you've got a code 14 in it, as mine did, the ECU is not seeing the ignition reference signal from the Igniter. The result is that the ECU will cut out the injector pulse, then restore it at the lower rpm.

Problem is, in testing mine I found the signal present at the ECU connector while running, varying between .4 and 1.35 volts. Now, spec says between .7 and 1.0 volts is a normal value, is the expanded range what's giving me issues? I have no voltage drop across any grounds and all power feeds are constant and steady. It will not reset the code 14, but the symptoms of it are still present. Incidentally the rpm will reach higher if the engine is cold, once warm it won't reach 2000.
Another incidental is the idle switch circuit IS functioning (according to my meter), yet the idle PID in the datastream always says "on" regardless of any conditional change.


25 years of fixing cars, but this one has me stumped.

Thanks for the replies! I checked for codes and there are NONE! I used a Hotwireto check and all I got were steady blinks. I changed fuel filter thinking it was clogged but it still does the same problem. Because there are no codes my best guess is the FUEL PRESSURE REGULATOR because I seen a video with what seemed to be the same problem for someone else and he said it was the Fuel pressure regulator. I cannot seem to figure out what the problem is. This weekend I will check air intake and the throttle body. Can anyone out there confirm or shed some light on the idea that it is my fuel pressure regulator?! @Metalhead1 @offroadnutz @Shady Cadence

Here is a link to a problem I had which is similar to what you are describing. Ended up being the fuel pump.

https://www.yotatech.com/forums/f115...000rpm-284002/

I had surging issues in the same rpm range as you but I could rev past 2k and it was fine once above that point. The problem for me was the tps sensor. I had just bought the rig and the previous owner replaced the tps, but didn't adjust it. Once I adjusted it the surge went away and has been good since.

I got transmission code 64 which is "
Severed lock–up solenoid or short circuit– severed wire harness or short circuit"

any ideas? I know its not fuel related because of a pressure test, and a replaced fuel filter. My problem is still happening and all i got is code 64.