97 limited 3.4L hesitates or stumbles when pushin' gas pedal...

[Lville_974Runner]

My 4Runner details:
1997 Limited 3.4L 4x4 w/ 238,000 miles. Still drives pretty good considering it needs a new suspension and radiators/water pump(over-heating issues).

This hesitation or stumbling/loss of powerstarted about 2.5 months ago just out of nowhere. One day I was driving it and noticed a slight hesitation at low speed(20-25mph). After a few seconds of slight jerking it would finally pick up power and move on. Once out on interstate is was fine. The next couple days it got worse and within a couple more days it started hesitating really bad when giving it gas making me scared to drive it to far from the house(let the AAA membership lapse).

The last time I had it running, a couple months ago, was in the garage and giving it gas and hearing a "restricted exhaust flow" sound which led me to think it might be catalytic converter clogged. I do have a small corrosion crack in my muffler too. I need new exhaust piping(catback) since mine is extremely corroded. Anyways, I also smelled the classic rotten eggs, but I've heard that's not always a sign of a bad catalytic conv. I never did check to see if it was glowing red hot, but so can't confirm that. My check engine light is on too, so I will get that scanned hopefully for free at O'Reilly's as soon as I make the time to do it. I'm scared if I try to drive it there and it's fuel related(bad fuel pump, filter, etc) then I'll have a tow fee that I can't afford right now on my hands.

I'm thinking about getting one of those OBDLink SX OBD-II Scan Tool USB Interface modules used with a laptop PC or an OBDII Bluetooth dongle with the torque app for my android phone, so I can be able to freely scan my truck when the dread CEL haunts me. Oh well, I guess it all starts with getting my truck scanned to see what codes it shoots back, as a starting point. I know this much, but I figured explaining my 4Runners symptoms might be a similar problem someone else had at one time and can sorta ease my mind as to what I need to do to fix and get my 4Runner running as good as she was just 4 months ago.

 

[bergeron37]

First things first, have you ever changed the spark plugs? 9 times out 10 this "studder" is a misfire and simply replacing the plugs solves the issue.

It did for me at least...

 

[BigNate]

This is about the exact way mine started acting at about 225k and it was a leaking head gasket.

 

[Tuco Tom]

I have a 2001 T4R that every once in a while hesitates when first starting out in the morning......then everything ok. Happens about once every 3 weeks?

 

[Lville_974Runner]

Thanks for the replies. bergeron37, I changed the spark plugs myself and the wires back last Summer. How could I check to know if it's a bad plug or wire? I'm sure if I pull and look at each plug it's gonna have carbon build up on it. I guess I could check for burn places in the plug wires because if memory serves me right, I had a friend help me and I didn't watch his every move. The truck ran fine up until just recently. The CEL has been on for a while now, and I probably should have had it checked when it first came on, but my excuse is laziness. It would sometimes go away and then come back on.

BigNate, how the heck can a leaking head gasket cause this? Was yours a full blown head gasket? If not, what did you do to fix the issue? Btw, I do check my oil frequently and I haven't noticed any foamy look which could indicate a blown head gasket, right? Also, I don't notice any "white" smoke, as from what I understand is an indicator of a blown head gasket.

Tuco Tom, well, I wish mine would go away on it's own, but, sadly, it's not...lol. The hesitation started out barely noticable and then got REALLY noticeable within about 4-5 days later of driving it.