I haven't had my 96 long, ran rough right after I got it. has 126 K miles. Cyl 2 misfire,replaced plugs, cap, rotor, 2 cans of Sea foam, nothing helped til I got the injectors professionally cleaned, ran good after that for about 50-100 miles, started to run a little rough again, Today it was really bad, lucky to make it home, scanner says multiple cyl misfire 1,2,3. I noticed a smell, something hot, looked under truck and my catayltic converter was cherry red. I unbolted and removed converter, still ran rough. Think my injectors are plugged again ? How can I keep them from plugging up? Is my converter bad ?Any ideas what my problem is ?

 

I would first replace the fuel filter. If the injectors keep getting clogged, that means that the fuel filter isn't doing its job.

I had a similar situation, turns out my wires were going bad. I run well now after new wires, and sparks, but still bad MPG.

I would say that you should work out a deal to get your injectors cleaned AND inspected. After that replace your sprakplugs, wires, and possibly cap and rotor. If the cat is glowing that usually means unburned fuel is getting there and causing it to get really hot.

 

Where is fuel filter located ? I read somwehre that it's under intake. I traced my fuel line, found no filter. probaly in fuel tank ? it'd be easy to install a universial filter near intake . I already replaced plugs, cap, wires, rotor.

 

http://4runners.org/writeups/fuelfilter/index.html

That should help with your fuel filter question. Hopefully that'll solve your problem.

 

I seriously doubt its the fuel filter or the injectors are causing it.

You have to be throwing codes. Pull those, and find out what they mean. I would lean towards TPS or Airflow meter. My 87 had the EXACT same problem, and it was the TPS.

For reference, the fuel filter should be bolted to the pass side frame rail, not under the intake. If someone told you that, they are retarded and have no idea what a fuel dampner is (the part they likely thought was a filter)

 

unburned fuel is a good call. Can it be run on a real scanner that shows sensor ranges to see if the tps is out of range? Ive seen my fuel filter under the truck. I thought mine was on the drivers frame rail near the seat area but, I'm not sure from memory.

 

Before my scanner says misfire #2. problem was clogged injector. I just spent the last 3 hrs removing fuel filter. My 96 tacoma 2.7- filter is located under intake plenum. and what a PITA ! I was able to loosen bolt toward front , but the rear one has a hose that goes to rear injector, I disconnected it there. to get to bolt on bracket of filter I had to remove engine fluid tube that runs right below filter. I think I'm going to replace tube with rubber, so it's easy to remove . That was the dumbest place to put a filter. wish the hoses were longer, I'd mount it on firewall.

 

I would check your valve clearances. Those are notorious for tight exhaust valves

 

You should cut open that fuel filter. Post a pic! Once it warms up I'll finish taking mine off and ten cut it open.

 

I am goiing to cut filter open. will let ya all know what I find. Will most likely get injectors cleaned again. No wonder Toyota says fuel filter is a lifetime part. next to impossible to get at without a lot of hassle.

 

toytech76 is right on, you could have valve problems. seen the problem a few times.

 

I think you guys are chasing the wrong problem going after fuel filters. Do some diag work and find the real problem. Everyone climbs on the fuel filter bandwagon and runs with it

 

A clogged fuel injector could cause a random cylinder misfire, but not with a with a cherry red cat. Besides I have rarely seen a clogged injector on a toyota since it has two filters including the one in the tank. It's unburnt fuel in the cat that causes it to glow red. The fuel filter is a waste of time in my opinion, and you wont find it as a maintanence item in your service manual either. If its has a 126,000 miles on it the check engine light would have come on a long time ago if the valves were to tight. Check your fuel trim if you have the software or look into the air flow meter. Your running rich and you should have a stored trouble code,

 

As a maintenance item, I always shake the fuel filters over a piece of white cardboard to see what sort of debris falls out of the intake side.

 

My CEL was on when I bought the truck.I appreciate all the suggestions I can get. I'm checking all possibilities. When I was checking compression with cyl #2 misfire 240 miles earlier, there was a very strong odor of fuel, engine was getting flooded. that injector was so clogged it had to be run thru injector cleaning machine twice.Mine was definitely clogged then, mechanic showed me the screen inside injector -it looked like the head of a Q-tip. you couldn't see the screen it was all fuzzy, he showed me a new screen, big difference.
As of Yesterday scanner says multiple cyl misfire 1,2,3. I'm thinking now I have 3 injectors dumping fuel. if cat got cherry red because of excess fuel, to me that makes sense. There is one more thing that I forgot to mention- Yesterday truck barely ran, I noticed when I got to about 3,600RPM it straightened out and ran pretty good, below 3600 RPM runs terrible. make any sense ?

 

Within the hr I'm going to use a cut off wheel and cutting the filter.

 

If fuel filter was doing it's job, dirt shouldn't be clogging the injectors. and they were definitely clogged 240 miles ago. ran great after I got injectors cleaned. Just wish I would've put a new filter on then, but didn't know where it was. I don't believe a filter can hold a lifetime of dirt. My Dodge 3500 diesel gets a new filter every 30 K miles and it's huge. My 69 firebird got a new inline universial filter every couple years, 5-10 K miles. Preventive maintenance.

 

will look into all possibilities til problem is solved. thanks.

 

wish you guys could see this in person. I cut inlet end of filter off first. it was VERY bad. I can't stress that enough. even before I cut filter- on outlet end I could see a streak of dirt inside. I took filter completely apart. it was unbelieveable. it was nothing but dirt. I removed my injectors, there was dirt streaks in fuel rail. will try to post pics.

 

yuck! you were right to replace that