dahkodah

looking for help before I go to a mechanic and start that process...98 4runner approx 170K miles...was running fine, literally all of a sudden at a red light the engine started running rough as if it was going to stall...it starts fine every time, mildly rough during idle in park but stutters when you give it gas until the RPMs come up...if you put it in gear it really gets rough and seems to be struggling but will drive and not stall...no warning lights until today the check engine came on...any suggestions or similar experiences...I want to resolve on my own if I can to reduce the cost...sorry for long thread and for any/all help

frodin1

Run by your local autoparts place and have them check the codes for you. That is of course you don't have a scanner? You can determine what happend by the code it gives and usually start repairs from there. If you dont know what the codes mean, the guys and "the few gals" on here can probably help you if they're in a good mood.

icerunner

#1 SUSPECT: Plug gaps as wide as, well, use your imagination! Remember 30,000 miles is close to max for standard 4 runner plugs

well anywho
Do you have a strange Noise as soon as you hit the pedal and a rough idle??
its probably "knocking" "pinging" or "pre-detonation" and time to replace your older plugs (asap).
This is a solution important to many who have had this issue and i've heard it come up many times on the forum, so I will comment.

#1 SUSPECT: Spark plugs
I personally have fouled out older plugs on my 99' SR5 4runner with techron injector cleaner. I bought the runner used at 75,ooo miles and for some reason I changed all the fluids but didn't even think of the older plugs... (and "older" is ANY standard 4runner plug with over 30K) I used techron fuel injector cleaner with 1/8 semi empty tank and drove 10 miles to the gas station to fill up as it indicates on the bottle. The only issue was that I drove it 10 miles to long......I should of added it at the gas station!!!
BIG MISTAKE and I knew right away what I did. knocking,pinging, a huge loss of power ect....
I really wanted to puke, as I thought I trashed my injector seals...
(Nothing worse than watching a grown man cry himself all the way to a gas station....
.....at 18 miles per hour)

SO, IF YOU HAVE A STRANGE NOISE WHEN YOU HIT THE PEDAL, I produced the exact same symptoms you have... knocking, loss of power. AT 170,ooo MILES...(DAM THAT's A LOT......) You may have put the last nail in the coffin on your aged sparkplugs.... pull them out and see if they look bad. (wide/worn/rounded electrodes and fouled out)

Remember 30,000 miles is close to max for standard 4 runner plugs AND remember DUEL ELECTRODE PLUGS ARE REQUIRED FOR THE 3.4 ENGINE (it says so right on the engine) BTW my plugs had 78K before I trashed them with chevron techron. Once they the plugs were replaced, I could not believe the power difference at accelaration and idle .....AND NO KNOCKING.

good luck and god speed

Yota Doc

That's easy. Whut he said. Made my job a little easier. Get that code and run by us.

dahkodah

thanks guys, a lot has changed except the symptoms, and no knocking and pinging, just stuttering in gear at low rpms until it gets going then seems to run fine until it shifts gears/drops to low range, give it gas and it smooths out...cleaned the MAF-which looked good,new pcv, changed the precat O2, then read about the TPS and accidently pulled that off thinking it was the MAF??don't know why, but put it back on...this TPS is very different from the previous models? yes? only 3 pins and no adjustment capability? anyways, no change...got a scanner and pulled the following 2 codes....can you guess? 0300 and 0306! # 6 is misfiring...honestly I can't remember when I worried about the damn plugs...the things been a tank and is really for the 3 mutts. I assume I start with the plugs and wires and worry about the coils later...is #6 on the passenger side under a coil? On the right correct...want to sart with that first to see if it makes the difference then change out the remaining...assuming this is the best and cheapest course of action at this point...let me know if I should consider any other options--thanks again

SEAIRESCUE

You should be able to meter out the 3 coil packs and wires to determine if they are good. May want to put a vacuum gage on the engine to see what it reads at idle. Low vacuum can be clogged converter, vacuum leak, low compression, etc.. Check it hot idle and report back with your findings. Also, if you can check the timing to see if it moves as engine revs. Look at engine block and see which side is more forward than the other. Most forward is #1 side which I think is passenger side.

My $0.02

dahkodah

when you hear hoof beats think horses not zebras...i changed out #6 and she purred like a kitten... oh well...changed the rest and we move on thanks for all the help and suggestions...still learned a lot

icerunner

Good to hear it, and glad to help and I'm glad the fix was an easy one. Thanks for getting back to us...