Ok, guys. I need some help. My 98 Tacoma with a 3.4 is having a rough idle. I notice it when I come to a stop. It's not like a miss. It idles rough the whole time. So I started cheap (my style) and tried running some injection cleaner through it. No help.

I got a fuel filter and I'm going to try that next. Plugs are newer (less than 20K), wires original, and I have a K & N filter. I got 112K on the clock.

Since I'm in the process of buying a house, I don't have a lot of cash to try different things. I was thinking that maybe it's time to do a MAF cleaning. I did some searches here, but haven't been able to find if the 96-98's can get a cleaning like the laters do.

Any Ideas? and Can a 98 MAF be cleaned?

 

Did you try pulling wires while idleing to see if it does not make a difference when you pull one? You could at least isolate the problem down to one cylindar/wire/plug/injector/etc...

 

ITs not as rough as when you'd lose a cylinder but I do notice that it shakes. I also noticed today that it takes a bit longer to start it. When I crank over the key it seems as though the starter has to work more to get it to run.

 

Anyone got an idea? I finnaly got some time this weekend and would like to try some attempts at it.

So can you clean the MAF on a 98?

 

Get two cans of Seafoam (do a search if you don't know what it is).

Run one can (1/3 at a time) through the intake via the PCV hose (follow directions).

Dump one can into a 1/4 tank of gas and drive it around about 10 miles, then go fill up.

If you have carbon buildup that is causing compression leaks on your intake or exhaust valves, this will get rid of it.

 

Thanks bamachem. What do you do? Just hold the PVC upright and dump some in?

I know there are alot of people on the board who don't like K & N's. COuld the oil from the filter crapped anything up? I've only cleaned it twice in the 50K I've had it in.

 

If you have an oiled filter, then you need to clean your MAF about every 7k-10k miles to keep the residue off. Use some carb cleaner, then follow that with electrical contact cleaner for the MAF.

For the seafoam, unplug the PCV hose at the PCV valve, turn the hose upward, and slowly pour in 1/3 can into the hose and it will be sucked into the intake. Shut off the engine and let it sit 20-30 min, then crank it up and slightly rev the engine while it smokes like crazy. When the smoke stops after about 5 min, then it's time for treatment number two.

On the second time, pour a little faster, and on the third time, have someone inside the vehicle and have them turn it off as you pour it as fast as it will take it. Let it sit for about 45min to an hour for the last time, then crank it up and blow all the smoke out again.

Pour the full 2nd can into the gas tank (1/8 to 1/4 tank of fuel) and drive it to a gas station and fill up. You'll probally want to get on the throttle some while it's concentrated to really clean the injectors good. Once you fill up, then the rest of the cleaner in the tank will break up any varnishing that you have in your fuel system and will finish cleaning the injectors and fuel rail.

 

First thing I would do is to clean the throttle body with carb cleaner and a toothbrush (usually does the trick). Might as well do the idle air control valve (IAC) while you are in there. If you are still running rough then check the air fliter (pull it out at idle to notice any change) and pull the plugs just to check the burn color on them (look for any black or non uniform ones which may help in diagnosis).

....I still bet the throttle body just needs a good cleaning tho...very common, I do it at every oil change now.

 

Jamie - I am cleaning out my tb this weekend, but question if you can use a carb cleaner for the job. The write-up in the tech section below says not to use carb cleaner, just wondering if you know more about this.

https://www.yotatech.com/~corey/tech...b/haveblue.htm

 

You should only use carb cleaner that says "sensor safe" on it.
There are some type labeled other things as well so you need to look at what it does and is it sensor safe.
Most of them nowadays are but you need to look at the fine print on the can before you buy it.

 

Well, I cleaned the air filter, throttle body(yuck, it is pretty filthy in there), cleaned the MAF, and threw a new fuel filter in it. It seems to have gone away.

The fuel filter was pretty plugged up, No fuel would come through the outlet when I turned it over. My air filter was dirty too.

As for the MAF, I can't see how you can really clean it. I see a very small wire down in it but I thought they were more accessable. I just sprayed electrical contact cleaner into it. How can you clean it with a q-tip? I'd be afraid of breaking that little wire.

 

Use a q-tip and a little bit of isopropyl alcohol to clean it. Don't use force just twirl it on the wire and it should do wonders.

 

I Agree With The Sea-foam. It Fixed The Rough Idle On My '01.