BOSTON4RUNNER

1997 4Runner SR5 5 speed 3.4 Liter

good running condition, but on the highway it began to buck, then ran rough, seems to rev up clean in nuetral but under a load running very rough not taking the gas.

water temp is fine, oil level is fine, no vaccuum leaks, did have some slight popping out the back, mild mild backfire, also engine itself sounds fine, no crazy mechanical noises coming from the engine etc...

check engine light came on and even flashed quite a few times, I plan to pull the code in a little while as I work for a transit authority and the maintenance department has a nice OBDII scanner.

Please respond with your thoughts....I wonder if it is a frozen gas line? or bad gas was 15 degrees here last night, I never had such a problem, but maybe I do now?

bamachem

i had that happen one time. it was a loose apark plug wire. engine all of a sudden ran like crap, missed, sputtered, etc and threw a CEL.

rimpainter.com

Yeah, get that CEL for us. That will help a ton in the diagnosis.

*Edit* Ha ha, I beat you Jamie!

MTL_4runner

Definately post the code number when you get it, but I would bet it was ignition related as well.

BOSTON4RUNNER

I had to get it in and out of the shop quick

It says number 4 cylinder mis fire,,,,,wasnt able to grab the code,,,forgot

that coil pack fired two different cylinders, I would think if it was a bad coil pack would show two misfires, but that might not necessarily be the case

maybe could be due to the fact I probably havent done plugs in well, lets just say a long long time

215k on the truck now, hasnt seen plugs recently will throw them in tonight, then if that doesnt do it move on to coil pack

BOSTON4RUNNER

hmmm also brings me to my next question, how often should plugs be changed in such a monster

and again my next does it seem, most often that people who are into cars, mechanics dont take better care of their own cars?

MTL_4runner

I would change the plugs anyway unless you have done them very recently (I do mine every 35-45k).
You might also take a quick look at this (could be something to look at):
http://www.los-gatos.ca.us/davidbu/toyota.html

Here was the final culprit:


Could also be a coil pack so I would do a quick check on that as well.

BOSTON4RUNNER

I did plug wires awhile back...as I had some misfires in the rain, wet weather

plugs,,,,,,um

should I say it

100k or so ago, maybe a tad more

are you guys going to burn me at the stake? put me in those wooden shackle things in the town square?

BOSTON4RUNNER

this is me, after you guys are done with me

bamachem

go get some from the dealer... about $1.75-$2 each. You'll need a ratchet w/ a long extension, a spark plug socket, and a 10mm socket to remove the coilpacks and the intake to the throttlebody. it will take you about 30-40 min to change them and get everything back together.

BOSTON4RUNNER

yes I have done them before

thanks for the refresher though, has been awhile

been too bust working on this sh-tbox that my truck suffered plug failure

this one has fresh plugs

roger

I think mechanics take professional pride in making their vehicles run as long as possible with the least maintenance.

What kind of engine is that you're building?

BOSTON4RUNNER

302 chevy, 650hp all together and running now

yeah so putting plugs in the Toy tonight,...

MTL_4runner

I was gonna guess a 383 stroker.
Give us a pic if you get a really nasty plug in there or if it ends up being something else.

BOSTON4RUNNER

I will and thanks alot to everyone

this forum is helpful to us all

when I get back form Costa Rica, I will add a page to my www.sfaboston.com website to outline the rear bumper build along with the lift and tires...in case it will be of help

I am betting on spark plugs, best case scenariio is that they have 60k on them, maybe ALOT more

BOSTON4RUNNER

here is the 383 stroker..that we built..with a blower

going in my friends 69 Camaro

this also will have fresh spark plugs!

BOSTON4RUNNER

FIXED!!!!

came home put plugs in, all the plugs looked good but the number 3 was nticebaly dark....but the OBD2 said the number 4 misfired, not 3

so maybe the mess up on 3 which indeed fired correctly, caused 4 to misfire

checked it on two different scanners

so it had Bosch plugs, took them out and swapped in new NGK

started the truck up, did the same thing sounded like absolute crap

pulled off number 3 plug wire,,,down near the end of the boot where it slides over the end of the sparg plug, even though you could not see a crack,,,halfway around the plug wire it was cracked

threw on a used plug wire I had, all set! will warranty the other wires

upon close inspection it looks as if there was adefect in the rubber/plastic sleeve that sits over the plug, almost like a rouch casting mark, or casting flaw you would see in cast iron, it definitely wasnt melted, the plug wire seems as if it was flawed at production

the wires have been in the truck for 5 months, guess it took that long for it to f-ck up this badly, but for awhile now I do think I had a very mild mis on the highway,,,probably a precursor to the final big crack and arc out

thanks again for the ideas and support

regards, tim