Bear80

I put a post over in the 4runner section but I think it should probably be asked here.

Lately my 94 4runner, (5 speed, manual hubs) has had varying gas mileage and a noticeable loss in power. Sometimes even as I drive I can feel the engine get slugish and then later I can feel it come back "alive." It isn't that noticeable but I can tell. Also sometimes it will run through serveral tanks of gas before I feel the engine run as is should again. Also when it is doing it's sluggish crap, it will run fine when it's first cranked and still in open loop mode, but as soon as it goes into closed loop it gets sluggish. Then there will be several tanks of gas that it runs great and gets gas mileage as it should. Anyone else notice this?? It seems to me to be a vacum device or maybe a failing sensor(temp?) Also I have put a new toyota O2 sensor so it's not that.

When it's running good I get 18-20 m/g and about 320 miles on a tank, when it's running sluggish I get 240 or so miles on a tank. I'd really like to fix this cause it's driving me nuts and also the 4runner is for sale and I don't like saleing anything that isn't 100%.

StevieC

Could be your injectors. They may be getting clogged or they may be intermittenly spraying poorly. The 3vze has an aux injector for cold start in open loop conditions which is why it will fun better in that particular condition. Just a thought.

No check engine light I assume?

Bear80

nope no cel, and the cold start injector only fires for a few seconds for cranking. I'm talking while the computer is in open loop, ie. using factory default programing with no sensor inputs. It usally takes about 5mins or so till the computer goes into closed loop. Because of this I seriously doubt injectors. Also when the engine goes from slugish to normal or normal to slugish, it's like someon turns a switch. Like a vacum device fouls up or a sensor starts kicking a bad signal.

DudeBud

still could be a code stored even know that there is no cel

AgRunner06

How in the world do you get 320 mpg out of your 3.0? I'm getting 15.5 in town right now. I'd look into the 02 sensor. You can try cleaning it or replacing it.

DudeBud

We used to get around 300-330 untill the light came on in my 90 even better on long trips

Bear80

see this leads me to belive this is a very common problem with the 3VZE. If you didn't buy it new or before the problem you'd never notice the less power and worse gas mileage. But the 3.0 should get you 20 or more miles per gallon with easy highway driving. I replaced my o2 sensor and only notice it ran smoother, not stronger or improve my mileage. TPS could be the problem, as in telling the computer it's back to idle when really it isn't. But I have a new one also. Anyone look into a vacum device?