My truck has a recent cap/rotor/plugs/o2/filter, injector cleaner in tank and some throttlebody cleaning. Sometimes I drive it and it accelerates fine, other times its jerky like i'm hitting bumps in the road, usually worst in 2k-3500 range. It will be jerky then I can park it and start it back up and it will run fine for the next short trip. When it runs well it runs really well, but when its in jerky mode, less power. I can floor it and its as if i'm towing something heavy, engine straining but no moving much. Literally goes back and forth from good to bad several times per day. No rhyme or reason. Fuel flow problem?? Put a new fuel filter about a year ago, that should be fine.

 

With all you done "basicly" a tune up. It does sound like a fuel delevery prob.when my fuel filter was bad/dirty it would idle good but soon as i tried pushing the pedal down it felt like no power & when i let off,It almosted stalled & when i was up to speed it would surge. I replaced the filter & my motor ran good again."also might wanna check that the fuel pump is working proper. I hope this helps.

 

I'm not exactly sure what you are talking about but, my 3vze is always "jerky" what kind of gas mileage do you get? Is it an auto or manual?

 

its a manual and I get about 12-13mi/gal. The jerkyness & power problem comes and goes consistently. It is an un-smooth acceleration, very faint, not even enough to see the rpm's reflect it. The power loss is significant, like i'm flooring it with a boat trailer attached. Only half of the time....and it won't be bad and become normal mid trip, or vice versa. If I get in and drive to the store, it will either be bad the whole way or good the whole way, intermitently for each full period that the engine is on. On average it runs good half the time and bad the other half.

 

Kinda sounds like an intermittent malfunction of the TPS or AFM.

 

sounds to me like it could be a sticky EGR valve if its occurring in the RPM range.

 

Based on my experience it sounds like the fuel pump relay over heating and then failing to put power to the pump. There's two relays...one in the engine bay with the other relays (AC, head lights etc...) and another behind the key lock and towards the heater. Know if it was me I would replace both relays (EFI and the one under the key lock towards the heater) before putting any more money into fixing the problem. That's me....and what was described happened to me to. Until I replaced both relays. Good luck. Note: I had a 95 Hilux 4x4 3VZE

 

Should I plug the vacuum tube to the egr for a day or two and see if I experience it still?



I wouldn't describe it as an actual complete fuel cutoff though, just un-smooth acceleration, like if you were lightly LIGHTLY tapping the brake 3-4 times per second while accelerating.

 

The 2-3k rpm range is where the EGR valve does most of its work, try disabling it for a while and see if the problem goes away.

 

I have the exact same problem on a '92 4runner (3vze) and have been through everything - full tune up completed yet hesitation (lack of power continues as LS1Steve describes). What steps were taken to rectify the problem? Did it end up being the fuel pump relays? I've been told by service techs that can't figure the problem out and that fuel pressure is good and that it likely is the ECU. Though - these are the same ASE techs that didn't even find that the rotor contacts and plugs were eroded to nubs. I am a very experienced after hours tinkerer that isn't afraid to go past elbows deep and have been given this vehicle because the previous owner finally gave up after throwing away well over $1000 at three different service shops that couldn't even fix the problem - one of the shops was a Toyota's only type shop. Very interested to know if you solved the power problem.

 

May be the fuel pump. Mine was doing the same thing months ago. Tried a number of different things to solve it. Wound up being the pump.

 

Thanks...though the plot thickens! I pulled the diagnostic codes thismorning and found that a 1-2 & 1-4 were indicated. Ignition open / RPM sensor error type stuff. Sooo...I reset the ECU and went for about an hour drive (with the diagnostic "test" drive jumpers in the diagnostic clip unit next to the battery) hitting every gear at all RPMs during highway and logging road driving (lots of steep hills) trying to get it to act up. Nothing!? No problems...no codes!? Hope it will act up so I can pinpoint the problem...

 

Seems odd hoping a problem will reoccur but I know exactly what you mean. For your peace of mind, I think you can count on it happening again...it's a 3vze.

Toyota developed this engine to limp along for hundreds of thousands of miles, with all sorts of mysterious maladies. Obviously their main objective was to drive all DIYers to frustration and eventually, insanity. Why else would we pour so much $ into these things. Oh, I almost forgot...whenever a 3vze discussion takes place, there has to be the obligatory reference to the 3.4 swap. Got to go now. I have to replace the evaporator in my 89 4runner.

 

Hey,

Yes I did solve the problem FINALLY the other day.... the TPS was bad.

The timing was correct with the bad TPS, so once I changed the TPS it ran smoother but the timing was now WAY off... after readjustment WOW it runs like brand new, feels like I gained 25hp!

 

Everything is now running as good as it should be...still not a real powerhouse of an engine though as many have said. This is my first experience with the 3vze and it is a real bugger to work on and trouble shoot for it to fun well! After my previous post I found that if I disconnected my (new) TPS it ran better? So took apart the cover of the AFM and fiddled a little...in combination with disconnecting/connecting the TPS no real improvement. Set things back to stock and installed a new O2 sensor...Cured! I had no codes or check engine light that would indicate a problem. Really pleased with the results. Thanks for your thoughts and suggestions.