Shudder - transmission or engine?

zcruiser

zcruiser

Senior Member
Need some ideas -- My '99 bucks and shudders when I'm running about 50-55mph and am trying to accelerate. Not a good situation to be in when I'm merging on the interstate. Also happens a bit when I'm at 70, but is the worst at 50-55. Seems to happen mostly when the engine is really lugging and I'm not in the optimum torque band.

I've taken the truck to a reputable tranny shop and they could not find a problem they could fix (they could have taken my money, but did not). There are no codes, though today I did see the 'Check Engine' light flash on & off a few times while trying to accelerate.

Truck has 148K miles, I am running 99.99% of the time in 2WD mode. O/D on or off makes no difference.

Engine electrical or transmission?
 
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A flashing check engine light is a warning of impending catalyst damage......I would guess engine.......Time to find out what the code is.
 
Flashing CEL can be misfires too. I'm guessing bad coil pack/boot. Or could be as simple as new plugs and wires if it's been a few years.
 
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Yes. I was just thinking misfires because mine did that a while back and it was a coil boot, but if it goes unchecked (or if it's too late), catalyst damage.
 
brian2sun said:
Yes. I was just thinking misfires because mine did that a while back and it was a coil boot, but if it goes unchecked (or if it's too late), catalyst damage.
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I wanted to see what the code was before getting too in depth but you may well be right.... hell, it could have the original spark plugs in it. :bravo:
 
Could very well be original plugs, but tranny shop did suggest plug wires / coil boot, thanks for the tips.

Sorry to sound like a noob, but 'catalyst' = 'catalytic converter'?

Going to Advance Auto today to pull the codes as this is the first time I've seen the CEL flash.

At least it's not likely to be the tranny, that would suck.
 
zcruiser said:
Could very well be original plugs, but tranny shop did suggest plug wires / coil boot, thanks for the tips.

Sorry to sound like a noob, but 'catalyst' = 'catalytic converter'?

Going to Advance Auto today to pull the codes as this is the first time I've seen the CEL flash.
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Yes, the catalytic converter....
If you've got NGK plugs in one head and Denso in the other they are original.
 
raydouble said:
Yes, the catalytic converter....
If you've got NGK plugs in one head and Denso in the other they are original.
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Man, I've got a lot to learn about 4Runner engines. It looks like to me there are only 3 coil packs, all on pass side (2-4-6), with plug wires running to the driver side plugs (1-3-5). Weird.

So why are there two types of plugs?
 
zcruiser said:
Man, I've got a lot to learn about 4Runner engines. It looks like to me there are only 3 coil packs, all on pass side (2-4-6), with plug wires running to the driver side plugs (1-3-5). Weird.

So why are there two types of plugs?
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I had always heard the heads were build in different factories, one came with 3 NGK's and the other one came with 3 Denso's (can't remember which)....here are the part numbers for the two plugs...NipponDenso # K16TR11 or NGK # BKR5EKB-11.
 
raydouble said:
I had always heard the heads were build in different factories, one came with 3 NGK's and the other one came with 3 Denso's (can't remember which)....here are the part numbers for the two plugs...NipponDenso # K16TR11 or NGK # BKR5EKB-11.
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Just bought 6 of the NGK's, will figure out how to change the plugs... Looks like a lot of the intake has to come off the pass side to get to them, and can then inspect the coil packs / boots.
 
If it comes back in a few days change the coil pack

i had the same problem thought I fixed it with plugs and wires, but came back a couple of days later put a new coil pack on and just like new
 
dkovac said:
If it comes back in a few days change the coil pack

i had the same problem thought I fixed it with plugs and wires, but came back a couple of days later put a new coil pack on and just like new
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No problems since replacing plugs. Took a trip up to the mountains (7 degrees in Boone, NC over the weekend) and had no issues pulling up the hills.
 
Same thing

zcruiser said:
No problems since replacing plugs. Took a trip up to the mountains (7 degrees in Boone, NC over the weekend) and had no issues pulling up the hills.
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Figured I'd mention that I just had the exact same problem and new plugs fixed it. If you accelerated hard on the highway at about 55, it would shudder slightly (not nearly as bad as the original poster describes). I was afraid it would be the tranny or something but 6 plugs later and the truck runs great. The problem is gone. the CEL never came on and the code reader didn't display any errors.
 
I had my 97 4Runner SR5 all of a sudden start shuddering on the highway. If I let off the gas it smoothed out. If I kept the gas around 50-60 it shuddered and at times pretty rough. If I accelerated it smoothed out some until I would resume speed around 50-60 then shudder again.

Does it sound similiar to the earlier posts? Hopefully just need plugs/wires and coil packs. I only see 3 of them, same as the earlier poster. Is that correct?

In case it is the throttle position sensor where on the engine is it? I assume up by the linkage but not sure.

Thanks for your help.
 
Most likely just the plugs. Start with the cheapest thing and go from there. The TPS is on the side of the throttle body.
 
Mine is also a 2000 v6 auto and running real lean & shuddering at about 2900 rpms, the exhaust is hot, converter is good, does this sound like your guys' also ?
 
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