gpcollen1

Well, I think I have mentioned my issue in various forums but here is where I am at...

I have a rough idle, apparent in both park and when you have it in drive with foot on the brake. In addition, it is rough throughout the full range of driving. I have not thrown a CEL. I have new tires that are properly balanced, to eliminate that as a vibration issue while driving.

At idle it is just rough - when driving, it feels a bit rough and like the engine is laboring a bit - starved for fuel?

I am at 128k and here is what I have done to date:

-Front A/F sensor at 100k
-MAF at 100k
-Cleaned throttle body a month or so ago - it was not that bad and did nothing to improve the idle
- Wires, plugs and PCV next
- Seafoam treatment after throttle body did not fix problem
- Timing belt - just a few weeks ago. everything went fine. Thought maybe I found the problem b/c the water pump leak had made so much crud build up around the drank gear and sensor.



No luck after the timing belt. Everything sounds a bit better with all new belts but the idle is still rough.

So now I am on to next step and plan on going through the following

Fuel - maybe injectors are dirty and the seafoam did not clear it up. I have done several additions to the tank. Should I buy a fuel pressure testing kit; do fuel pumps ever gradually go and just not give you enough fuel; just pay the $$ and have the dealer do the injector cleaning - the one the attache right to the rail.

Vacuum - I used a test my buddy told me b/c there was no obvious sign of a vacuum leak. Used my torch and released propane around all the hose connections and hoses. He said you will hear the idle change if it sucks in the propane. Nothing there!

I am just getting a bit frustrated at this point. I don't mind doing the work or spending the money. This is the first time since I was 17 that I was contemplating having a mechanic look at it - though that even pains me to say.

Guess I am looking for any experience or other low hanging fruit to pick!

Thanks
George

mkgarrison5

how much seafaom did you use in your pcv?? use a whole can.. make sure your plugs are gapped properly and use factory densos if possible.. cold air can kill gas mileage... just some thoughts

gpcollen1

Started with 1/3 can and worked up to whole can. Nice smoke show but no results. Densos properly gapped. With a rough running vehicle, gas mileage will obviously suffer as it has.

I think I have hit most of the elementary BS but sanity checks are nice.

mkgarrison5

just some questions, is everything you put on it from the yota factory? sometimes when you mix and match stuff your truck wont like it..

MTL_4runner

You might also have a plugged converter....something to check anyway.
You should also be doing a compression test to ensure you don't have a cylinder with low compression.

Did this rough idle happen all of a sudden or has it slowly gotten worse over time?
Was the truck worked on or did something happen just prior to this occuring?

mkgarrison5

how do find this out? isnt the converter welded onto the pipe??

MTL_4runner

http://www.aa1car.com/library/converter.htm

mkgarrison5

thanks for the link mtl.. very interesting

gpcollen1

I guess it kind of crept up on me. I was trying to find new tires and mine were getting out of balance. I figured that was the vibration when driving on the highway. New tires and balanced and still the vibration. More noticeable now at idle. No specific event to point to when it started.

Nw that I think of it, it may have even gotten a tad worse after seafoam treatments -not a major jump worse - and it may be coincidence but it is a bit worse than before I cleaned the throttle body. So maybe the Converter is on its way out.

Compression should be checked this weekend - was thinking maybe a valve sticking. Think I should double check timing with my ligh to make sure timing is not jumping around.

gpcollen1

Interesting read. I guess the Cat is a definite possibility. i just thought that I would get a CEL prior to it causing an issue like this. Ill put it on the list to explore.

mkgarrison5

see i was thinking that the seafoam treatments could aid in clogging the Cat.. do you think this could be a possibility?? bc it does loosen up stuff and send it down the pipe ya know??

MTL_4runner

Yep......that's why I always recommend running 1-2 cans in the gastank first, then directly in the engine.

gpcollen1

If it is the CAT - I gaurantee it did not help it!

MTL_4runner

I'm not totally convinced the cat is the cause if your issue, just something to check though.

mkgarrison5

what is the difference in before or after? just curious

GOH10 Runner

I had a similar problem and it turned out to be a bad fuel injector.

MTL_4runner

Basically doing it via the gastank cuts through the carbon more slowly because it is diluted with gas (then later when you put it through the intake, it cleans the last little bit remaining). When you just dump it in the intake, all the carbon will come loose at once and can foul spark plugs, damage O2 sensors and even plug the converter.

MTL_4runner

Did yours throw a CEL when it went bad?
I ask because usually you see a misfire code with a bad injector.

GOH10 Runner

^ Yes I did throw a CEL, but not for about a week or two of the symptoms

gpcollen1

It has been over a month for me so far.