Charecter1

Hey guys, I just recently bought a 93 4runner and I thought this would be the best place to go for my issue on the 4runner. First off its a 3.0 v6 with cold air intake and 211,000 miles. I started noticing that the truck will not accelerate what so ever after a few minutes of driving. It accelerates fine after just starting it but then a couple minutes later, it falls flat on its face and takes a while to get to 20mph. The weird thing is though is that when it goes to ˟˟˟˟, if I turn it off and turn it back on, it runs fine again and then a few minutes later craps out. It idles fine and does not have a misfire. I pulled the codes and it's telling me it's all clear. Please help, I don't know what to do.

stomper4x4

Sounds like it might be a partly clogged fuel filter to me. At idle, enough fuel goes through, but when you accelerate and need more fuel, not enough is getting though. And maybe after shutting it down enough pressure is in the system to squeeze fuel through for it to run smoothly for a bit. Just a thought.

IronsmanMedic

I picked up a 93 3VZE 'runner a few months back and she could barely get up to freeway speeds and struggled badly to do so - even with ECT on. Although I've done a fair amount of work to her so far, I didn't have to do much beyond a VERY thorough tune-up to get her running at what I felt was acceptable speed (I can hit 90 now) and acceptable acceleration. All of the following also increased my MPG from about 13ish to about 20+ (no joke).

1. Replace all vacuum lines and make sure they're routed per FSM (I can't stress enough to you how important this is)

2. Replace all hose clamps (I'm OCD and like to know I have solid connections EVERYWHERE)

3. Fuel filter (WIX, I think)

4. Spark plugs (NGK [or Denso...eff Bosch!!!])

5. Wires (Import Direct [or Toyota, nothing else])

6. Distributor cap and rotor (Import Direct [or Toyota, nothing else])

7. Air filter (WIX, I think)

8. Oil change x 2 (the day after I bought her and 1,500 miles later), using Castrol High Mileage 10W40. *I'm doing another change at 1,500 and then will start the standard 3 mos/3,000 miles OCI.

9. Radiator/cooling system clean & flush and then TOYOTA RED coolant, with new upper and lower rad hoses and a new TOYOTA thermostat!

10. New Radiator cap

11. New Fuel cap

The above got my acceleration to acceptable and about 18mpg. Just did new injectors (Flamethrower) about a month ago, along with the obvious new plenum and throttle body gaskets, and that bumped me to about 20mpg (maybe 22mpg on a good week). While I had the intake off, I cleaned the sheeeeeIT out of everything, inside and out, including EGR. I also replaced the Throttle Position Sensor (TPS) and Fuel Pressure Regulator Vacuum Control Valve (FPR VCV) since the TPS didn't pass FSM testing and the FPR VCV didn't work. Speaking of testing, in addition to doing the aforementioned replacements (which doesn't cost much and doesn't take much time to do, except for the fuel filter, which isn't hard but is a bit time consuming), make sure you get a multimeter (if you don't already have one) and test everything you encounter...every plug, every connection, every sensor, etc. It's a quick way to determine what is within spec and what is not. Make a list of things that don't check out and start going down the list as $$$ and time permits.

Once you have access to a multimeter, check the following right away:

Throttle Position Sensor
Volume Air Flow Meter (VAFM) *DO NOT ATTEMPT TO ACCESS THE VAFM VIA THE TWO SCREWS ATOP YOUR AIR BOX!!!
O2 sensor(s)
Temperature Sensor
Oil Pressure Sensor

I also went through and replaced every hose I could get my hands on (removing the intake plenum will reveal hoses that you can't easily access w/o the plenum off). I had to go to NAPA for the brake booster hose and correct fitting upper and lower rad hose, but all other hoses were available at Autozone and O'reilly. When you have the plenum off (for whatever reason), that would be a good time to swap out valve cover gasket AND your PCV valve and PCV valve grommet. *You'll find plenty of threads here about the 3VZE PCV, including ways to reroute it so changing it in the future is easier and doesn't require removing the plenum. I left mine in the stock position though. I like taking everything apart...not only do I get quicker at working on my truck each time but it also affords me the opportunity to memorize where everything goes (like the vacuum lines) and allows me to check things each time I tear her down and spot things that may be "wrong."

While the 3VZE may not win you any 1/4 mile championships, my new ol' girl has enough guts to battle the Southern CA freeways with some to spare.

Gevo

You get 18-20 mpg????

Man I'm jealous!

As soon as I put on my new injectors (tan flamethrowers) my code 52 went from very intermittent to very solid. But before, the best I've gotten was 16. This is average hwy and streets. Only hwy I got about 17-18. Of course with code 52 mpg speak is irrelevant.

Anyway, on topic now!

your symptoms are exactly what my code 52 does. But you say you don't have codes...
Check your timing, although it can't change during driving, set it to 10 degrees btdc. This will eliminate timing as a problem.

And as ironsman said, do a good tuneup and clean everything.

IronsmanMedic

P.S. The rule of thumb I use when dealing with used cars (purchased private party) is "God only knows what has and/or has not been done to this thing." Accordingly, I approach the vehicle from a worst case scenario position and start with the basics and keep digging (repairing, replacing, etc.) as I go. Start with the easy tasks (tune up stuff) and then move on to the more difficult.

Being OCD, I also keep strict records...what I did, date and mileage that I did it at, and keep all receipts. Not only so I can track what I did and when, but it will allow me to track how much money I'm putting into the truck AND will allow any future owners to know what has been done and when.

I'm currently putting together a parts list (of everything I've changed) and may post it up here for my future reference and to aid others. Most of the stuff I've done, I have part numbers for Toyo, Autozone, O'reilly, and NAPA (I like to price compare). :-)

IronsmanMedic

Finally, save this URL http://personal.utulsa.edu/~nathan-buchanan/93fsm/

If you have an iPhone or Android based phone, visit that URL from your phone and then take whatever steps your phone requires to "Save to Home Screen." This way, if you ever need to access the FSM from your phone, it's literally one click away. Each time you access the engine section, make sure you are viewing the 3VZE section or you'll likely find yourself thoroughly confused. LOL

Gevo

The fsm and wiring diagrams are LITERALLY one of the 5 always active tabs in my android browser

IronsmanMedic

Ditto. Yotatech is always up within my browser too.

Gevo

Sorry to hijack the thread slightly... but I had to share

jgreenyoda

Is it standard or automatic Transmission and when you encounter this problem what is the engine running condition

Charecter1

It's an automatic. When the problem starts, the engine seems to be running fine, just some misfire. I'll try a full tune up but everything is so much more expensive on this truck compared to my 96 f250. 😐

Charecter1

so i replaced the spark plugs and wires plus the cap and rotor so now it accelerates a lot better at start up but it still doesnt run like it should. when i set its timing to factory specs, it would hardly run. it doesnt make sense.

Gevo

I don't really understand what's going on exactly so someone with more knowledge will eventually stop by. How advancing your timing is giving you worse performance is related to fuel and air, I'm not sure.

Have you checked the pick-up coils in the distributor if they are to spec? Those things relay the cam position to the computer and that's how the timing process starts. Admittedly I'm not sure how that would relate to engine performance when adjusting the timing up or down.

Sorry can't be more help. As I mentioned in a similar thread, you really have to go to each component in the engine bay and check it for proper operation.

Charecter1

I'm stumped too on this one, thanks for the advice. I might just take it to a shop. But last night I was reading about the icm and what it does when it goes bad. Although my truck starts fine and doesn't die, it has the poor acceleration. When the grease on those things wear out, they get hot and malfunction, so I'm wondering if that might be my problem.

Punchy

Any Air leaks in the SRS tubes? As the engine heats up and the rubber soften the air leaks get bigger.


Possibility that the Vacuum lines to the EGR/PAIR/FPR VSVs are not correct.

Charecter1

I'm going to be running a vacuum test tomorrow and see if I have any leaks. I have a feeling my egr doesn't work

Charecter1

I ran a vacuum test and the gauge read normal at idle and when open throttle, the needle would decrease to about 3 and go over 20 and then settle back down to 18 which is a sign of no vacuum leaks.

jgreenyoda

It sounds like it could be a transmission issue check fluid level and condition when its warmed up after a short drive check while running on level ground of course and if it looks bad do a fluid change along with filter swap couldnt hurt if you havnt done this already i also like to get a chilton or haynes manual for all used vehicles i buy saves on headaches