artinge3

Hey guys,

I've been reading the forums for awhile but haven't signed up till now.
I have a 1990, v6 3.0L automatic 4 runner with 220,000 km on it.

Recently everything has shat out on me and the mechanics didn't seem to be doing a good job, had it in the shop 4 times and it was broken down/ needed towing within 24 hours each time of getting it out.....soo i have decided to take on the problems myself.

For the past month or so my fuel economy has gone to , and the engine started to lag when driving over 100km/hr on flat or over 70km/hr up hills. From my best guesses i figured that this ment that my oxygen sensor was bad.....so i replaced that little sucker and it seems to have made the problem slightly less bad, but it still definatly persists. ......so to me this possible means that the catalytic converter is toast, but i am not sure how that works or causes engine lag or anything??

So.....any ideas what it could be?
How would the catalytic converter cause engine lag?
What are the repercussions of putting in straight pipes?

A long time ago i thought the problem could be related to the fuel filter....i asked the mechanics to check it out and they never said anything was bad with it.....but who knows....the vehicle smells like gas a lot fo the time now too, only when or right after driving...this could be an unrelated problem...

No check engine codes come up either.... at one point they poped up on me persistantly, so i took it in paid out the ass to have them tell me it was likely a faulty connection cuz no codes came up.....so i replaced the battery. Now the check engine light has only come up once....but disappeared like 1/2 hour after.

Any help or suggestions, explanations would be great!!
Thanks for your time!

Piiiiice!

Hilux808

Your fuel filter could be bad or plugging up. It's an often over-looked part. My 91 4Runner calls for the filter being replaced every 30k miles, I'm assuming it's the same for the V6's. As for your CAT, my 4Runner is coming up on 200k miles and I just replaced it with a striaght pipe from e-bay. Look up RMT performance. It did help out as the engine can breathe easier and the fact that the CAT was the original it wasn't flowing like it should. If your cat gets plugged then the engine can't get rid of the exhaust fast enough. This will seroiously affect power output. Check your AFM too to make sure everything checks out, this turns on the fuel pump and also controls the EFI & drivability issues. Also the coolant/engine temp sensor, make sure this is working. you can check with an ohm meter/DMM. I replaced mine out and that really helped with drivability and at idle.

rdlsz24

If it smells like gas after driving and you are getting bad gas mileage I would definately check for a leak first. The gas line coming out of the top of my tank had rusted through and was spraying gas under pressure.

Rob

machabees

When I attempted to replace my fuel filter my lines were really rusty. I sprayed them down with PB but I am still worried about breaking the lines when I attempt to remove it so I haven't tried yet. Any suggestions to that effect?

Jay351

Does the cat/mid pipe turn red after a long drive? If so then your cat is probibly plugged. If you got over 100k on your stock one I would replace it with a hi-flow aftermarket. I got my magnaflow from lordco for like 110 bucks (stainless version). You can get about 50-100 bucks for your oem cat from the scrap people due to the small amount of platinum inside.

Where did you take your truck to have the codes pulled? I would be pretty pissed off since you can check them with a paper clip.

I would check for any codes just to be safe, sometimes a code is not "strong" enough to throw the CEL itself.

What kind of O2 sensor did you replace the stocker with?

artinge3

yeah that sounds good, thanks for the advice, i'm gonna check out all that stuff as much as i can, someone else was telling me about a ed up distributor cap or a wire leading to it could be the problem.

I took it too a well respected place in north van, Aj transmission and automotive....but i guess i don't respect them soo well anymore.

I just grabbed the fitting o2 sensor they had on hand at North shore auto parts because i was so sure that was the problem and easy fix. It was $175, the one form the toyota dealer woulda been $275.

My gas tank is pretty much always pressurized. I try to let it out as much as i can and not put the cap on tight ....i'm sure that factors into something somewhere.

artinge3

So we took out the CAT, and that deffy wasn't the problem, but you can hear it miss firing when going up hill, and it starts as a single piston and you don't feel much lag, then as you give it more gas or steeper grade it miss fires more and starts to lag out. .................the distributor cap and everything is working fine....so i guess that leads me to the AFM, but i am not sure how to check this or disconnect it? I think i found it ...but not sure what to do to/ with it. Do these symptons add up? for a AFM and what do i do with it?

We looked for a fuel leak too and tried towing some to see if it would spray/ leak more under stress but nothing happpend....so maybe fuel filter....but i'll change that anyways soon.

help?

artinge3

Seems everyone is having a lot of problems right now.

artinge3

Soooo......changed the fuel filter now too, and checked for fuel leaks. Nothing, problem still persists. So now i am looking at the fuel injectors, is there an easy way to clean them or flush the whole system? or do i have to buy new ones?