Cuthroat72

I have a '99 4runner, 3.4L 5 speed that is giving me some trouble. It has 189,000 miles on it, and there is what I think is a fueling issue. When you let off of the throttle and allow it to slow down to around 1500 rpm, it stutters and bucks when rolling heavily back into the gas. Above 1800 it's clear sailing. I'm not sure whether it's something as simple as sparkplugs or a fuel filter, or more complex like injectors. If anyone has any suggestions, I would love to hear them. I am currently running some fuel injector cleaner through the motor to see if that will help give me any clues. Much thanks!

fillsrunner4

Ide change the plugs wires and fuel filter if you havent done them before. Thats first. Also take a good look at the spark plugs as they can tell you some as far as if theres oil passing through rings or unburned gas. ect... Ide do those and see if it helps some

ciscojay

You may be due for a good 'ol Seafoam treatment through the induction system. Could be your vacuum lines are clogged up. Run some BG44k through the tank and get a bottle of Seafoam and see how it runs after that.

Cuthroat72

Sounds like a good starting point. I won't be able to follow up with those suggestions until the middle of next week. I have some final exams to get out of the way.

Hoopster

Is your check engine light on? I would start with all the easy/cheap stuff first. Air filter, fuel filter, plugs, wires, etc. Then disconnect the battery for a minute to reset the ecu. Drive for a few times and see what happens.

Cuthroat72

No check engine light. (I even turned the engine off and turned it to on to make sure I hadn't blown a bulb in the dash!!!) I will definitely check the cheap stuff 1st. Last thing I want for Christmas is a big mechanical bill to tell me it was a bad plug-wire!! Ha! I really appreciate all of the input. I only signed up this afternoon, and the response has been great!

jukeit

'99 Automatic with 140,000 and I'm having the exact same problem. I just changed the plugs over the weekend. One was suspect, but there wasn't any completely obvious problem. Ran OK for about 40 miles after the change, but the problem is still there. I did not change the wires or coil packs, but with the OK condition of the plugs, I thought I would start with the fuel filter next. That's what I was searching for when I ran across the post. Will be interesting to see if we have the same resolution.

ugadawg95

Are they original wires? I had the same problem at around 140K and it was the wires. I'd start with he plugs/wires. Then check your throttle body and see if it may be in need of cleaning. I'd change the fuel filter if it is the original. Some say the fuel filter is a 'life of vehicle' part. I changed mine. It wasn't that much and I know its clean. Then do the seafoam. I do the seafoam every 30K. The search button is your friend if you need help doing any of that. There are a bunch of knowledgeable people on this board and a plethora of information!!! Good luck!

jukeit

Thanks for the info. I assumed that if there were problems with the wires, I would see the effects in a fouled plug. Is that not the case? I'll definitely give the throttle body a cleaning....didn't think about that and will search for that as well. Thanks again.

ugadawg95

I didnt have a fouled plug. But the wire came apart in my hand when I took it off one of the plugs. It was shot!

seanz0rz

had a similar issue on mine, would studder and buck at about 1800 rpm, changed plugs and wires, and solved my problem!

Elvota

My local AutoZone loans out OBDII scanners. You might see if the local chain store in your area does the same.

Even without the engine light, you might get some information to send you looking in the right direction. Post up any codes you find or take a look through these.

https://www.yotatech.com/forums/f128...e-codes-76363/

Toyota specific more towards the bottom of the list.

Plus... it wouldn't cost you a dime to borrow the scan tool.

(They most likely will require a deposit or run your CC, but that is fully refundable upon the tools return.)

Cuthroat72

I changed the fuel filter about 15,000 ago, but I am not sure if the plugs/wires got changed at the last tune up. It kinda sucks being 100 miles from the garage and tools. To this point I have not noticed any difference with fuel injector cleaner, but I have only put about 60 miles of stop and start driving on it. I will put another hundred on it on wednesday when I head home for the holidays. I am hoping it turns out to be the wires and plugs because I only have 2 weeks off for school and want to start on a bumper for it. I can't really work on it if it is in someone else's shop gettin some major overhaul, ya know?

Cuthroat72

Since we're on the topic, is there any particular brand of sparkplug or wires that I should avoid. A friend of mine had trouble when he went with a higher tech plug in his saturn... turns out the cheaper ones worked better. Of course the last set of spark plugs I installed was on an old early bronco (my other toy)

seanz0rz

go to the dealer and buy plugs for your vehicle. make sure they are denso, and are dual electrode. you can order these from northridge toyota, which i recommend. as for plug wires, if you dont want to spend 60 bucks at the dealer, i picked up a set of NGK wires from somewhere on the net for about 35 bucks.

only stick with denso or NGK plugs, many people have horrible experiences with bosch and others.

Cuthroat72

Thanks! I have to drive past 2 toyota dealerships on the way home, so hopefully I will have parts in hand when I get to the house!

seanz0rz

mine had the spark plugs in stock, not sure about the wires.

icerunner

1) Check the Spark Plugs 1st.......when was the last time the plugs were changed out?

2) If you change the spark plugs and the issue persists Change the Plug Wires.

3) Check the MAss Air Flow Sensor or MAF Spray "MAF cleaner" on it but be careful not to touch the wire as it is a sensative sensor.

4) clean the throttle body...

5) run techron injector cleaner through the gas tank....after you change the spark plugs ....if your plugs are "semi fouled" the techron will foul them worse....trust me on that one.... i barly made it home one day after I pulled that stunt...


6) Fill up with BP/amaco Ultimate or Shell "V Power" in the gas tank for a few tank fills...

good luck and god speed
ice runner over and out

icerunner

FYI:
"Champion Toyota" has free shipping and 25% off for yota tech members
I buy from them all the time that ship quick and have good customer service.

Cuthroat72

So new plugs and wires did the trick. It runs like a scalded dog now! Now if I could only figure out how to program the Mikado garage door opener....