I have a 94 4Runner. 3.0 with a 5 speed. Couple days ago driving home from dinner it start bucking and jumping in 2-5 gear.(It’s a manual). It’s got a terrible lack of power. So started with fuel and put new fuel pump and filter along with a FPR. Didn’t change anything. Then tried air. New TPS and air filter cleaned everything out with MAF cleaner. Same thing still nothing changed. So then I went to spark. Did the distributor rotor and cap as it looked like I had some rotor strikes on the cap. Went to TDC on cylinder one set the distributor in and set timing. Confirmed with timing light that it’s BTDC -10. But when I jumped the diagnostic terminals I went to go look at code and I got no lights no diagnostic flashes and not even the continuous 2 flashes telling me there is no code. So I’m concerned that when I jump the terminals for timing purposes it’s not going right. Has anyone else had issues with there diagnostic plug? I got the timing cover off tonight to check timing for both cams but haven’t spun it to check. I also did compression tests with cylinders all within 5psi. Could a knock sensor cause this problem? Before I do the timing belt I wanna make sure I’ve exhausted all options. I’m at my wits end and at the mercy of the forum Gods. Please help

 

Still haven’t figured this out. Any help would be greatly appreciated.

 

When you turn the key to the "on" position does the "check engine" light up with the other warning lights? And if so. I'll assume it goes off after starting?
Just sitting there idling, with hood open, is there any indication of a running issue, or does it idle fine?

 

Put a vacuum gauge on it.
How old is the catalytic converter? Could it be plugged, restricting the exhaust?
vac gauge will tell.

 

I was thinking plugged exhaust as well

 

So the guy I bought the 4Runner from removed the cats. It has a flow master 40 and exhaust pressure seems good. I haven’t checked vacuum but I have checked all of the vacuum lines and they seem to be intact. To JimKola I have no check engine light at all possibly the bulb is out. I’ll grab a new one tomorrow. I have the intake torn down at the moment to replace the knock sensor as the wires were pretty gnarly headed down under the manifold.

 

The reason I ask is if the bulb is there, and not burned out, it should light when vehicle turned on. Not working may indicate issue with ECU. Would explain why pulling codes has been a problem. Also, the p.o. may have pulled the bulb if it was staying on while running.

 

Gotcha I will pull the dash first thing in the morning and check. If it is an ECU issue, can I get a used one reflashed or must I buy a new one? Thank you for the quick reply.

 

You can get used, but first things first. See if the bulb is there, and working. Those ecu’s are pretty solid, about the only thing they didn’t like is water and getting back fed power through a ground. You can easily open the lid and inspect the circuit board for damage. It’s usually pretty obvious. I’ve also known people to repair their own.

Are you using a FSM?

 

Alright will do. I am a scholar of YouTube I haven’t used an FSM. But I do study and do my due diligence before diving into a project. I will check the light in the morning only thing that worries me is that I had an another dash in that had a working oil pressure gauge but not speedo. I had to take in it for Safety Inspection so I swapped for the one with working speedo and was going to get aftermarket OP gauge but when I checked for codes on that one I also got no CEL whatsoever.

 

It also had A/C but PO also took all components for that out as well. Do you know where I would place a vacuum gauge to check for vacuum?

 

Your vehicle will require some patience. I've found that when some owners decide to eliminate components they can do it in many , let's say interesting, ways.
Maybe a good place to start:
1) get a Factory Service Manual.(not Haynes or Chilton) acquiring a Toyota EWD to go along with the FSM would be even better.
2) look under the dash, both kick panels, and hood for factory wires that have been cut and reconnected using crimp connectors. I'd take them apart, solder, and shrink tube. If you find wires twisted together and wrapped in electrical tape then you really know you've got some work to do.
3) don't assume vacuum tubing is connected properly just because it's plugged into something. Those vacuum routing diagrams aren't the most fun to read, but if you really stare at it long enough they start to make sense.
4)If you see non-factory wiring try and figure out what it does and remove it if you can. Odds are it's not needed. Aftermarket alarms(meh), stereo systems, and added lighting were common sources of added wiring. The aftermarket alarms were particularly bad.

Once you get things back to the way Toyota intended you can really start diagnosing things properly.

 

So I checked if the bulb was out with another bulb that I know works and still no CEL.

 

I don't have elect. diagrams for a 1994. I'm sure someone here does. I'd have to guess that either the wire from the ecu to the bulb has been cut, or there's an issue with the ecu itself. I'd make sure the wire is ok first, but you can pull the ecu and inspect all the wiring in the right kick panel, then open up the ecu and inspect the circuit board. Replacing an ecu is always last on the list.

 

I checked in the kick panel and I have one purple wire cut. I’ll look into a wiring diagram now. Thank you so much man

 

Just started randomly?
did you just get fuel? Go to the car wash? Drive in pouring rain etc. You get the Pic.
Ok it just started...
Throwing the book at it hasn't been effective yet.
You can cut your work in half by determining if the issue is fuel or fire.
Jimkola will give you great direction to determining that.
my best advice would be to take a deep breath, drink a 🍺 and be methodical.

 

You can put a vac gauge anywhere on the intake plenum where there is constant vacuum while it’s running. One of the ports that goes to the power steering pump would probably work well. Then read the gauge activity compared to any of the charts you find on the net.
https://www.google.com/search?rlz=1C...pRHj5aRIn5t8JM

 

Generally speaking jerking and backfire are a timing issue...
just sayin

 

874runner I live in Hilo. I get a down pour a day. There really wasn’t anything out of the ordinary. It had a long crank most times but that was about it. When I start it now it idles just fine until I touch the throttle then it starts throwing a tantrum. I checked timing on the cams and with a light and it’s good.

 

Thanks man! That’s a super helpful picture.