nrgetic99

Drove from VA down to the Outer Banks of NC for some R&R.

About 2 hrs in, I have the cruise set at 60 mph (Route 158 if you know the area is a big speedtrap) and vehicle starts to miss badly. Take if off cruise, run manually at same speed (~ 1900 rpm in top) and same result.

Seems fine under acceleration but will not run right at cruising speed.

Decide I should try and make it to the beach house and check a few things, plugs are new and clean, no obvious loose wires or vac hoses.

Tank was about 1/3 full so I pick up some FI system cleaner and fill tank with Shell V -power premium (contains highest additive level of any commercial gas right now) and it seems to run fine. Before coming home, fill up again with V-power premium ands dunk rest of FI cleaner in tank. Runs just fine all the way home.

I hooked up my OBD-II tool last night, no codes or pending codes, no misfires detected.

This leads me to the following :

1. Bad Gas ?
2. Intermittent coil pack/plug wire breakdown ?
3. Clogged injectors (hence OK under full accel but struggle on low revs)

Anyone got any ideas ? I will replace plug wire (Genuine OEM only ) when funds allow

Thanks

David

P.S. Drove on the beach and got some nice comments about my deflators and low budget on board air set up... peoples faces when they see me hook up an airline under my rear bumper are worth seeing

UNR.Grad

I had the exact same problem, same speed and everything. Then later the next day it got worse at lower speeds, always at low RPM. A code popped up and it was P0303 "Cylinder #3 Misfire" code I tried to replace the plugs (Denso dual electrode) and coils (NKG) today but that made it worse. I switched the coils back to the old OEMs and same problem, so it's not the after market coils. Any ideas? What did yours end up being?

The old plugs looked very worn. I did not gap the new plugs, they all looked good from the factory denso box.

UNR.Grad

Any help would be appreciated guys, I have to move this weekend and don't want to take it to the dealer. $$$!!!!!

aowRS

How about a partially-clogged fuel filter?



Andreas

frodin1

We had a similar issue on a newer JEtta and it turned out to be a bad coil pack. Just a thought?

Kevinshoemake3

Maybe try cleaning the MAF sensor. I had a very similar problem and this solved my problem. Worth a shot (a can only costs 5 or 6 bucks).

Hope ithis helps someone out there.

Kevin

97ltd4x4

with a po303,#3 cylinder misfire.I would try and get the code to move to another cylinder.ie,move coil#3 to #1,still misfire on #3?..move plug to #1..still missfire on #3?..really inspect wiring harness for turning on and off coil #3 ,tests ok..still misfire on #3?...Switch injector to #1...still missfire on #3...compression and leakdown test to #3...Thats it.

If you do all those things you will find your problem,most likely ignition,followed by fuel,followed by compression...low RPM/light load almost always is ignition,either primary or secondary...fuel and compression will get worse as RPM/load increases if those are out of spec.

Also,things that cause multipe misfire codes are either : all worn down plugs,shared coil pack,MAF,vaccum leaks,bad gas,ect.

hause64oz

Can someone elaborate on how to clean the MAF?? Im having the same problem with my 3rd gen. I thought it might be the fuel pump as I just had all my fluids flushed, injector service and tune up with all new plugs and intake cleaned out, and new fuel filter... MAF and fuel pump seem like the last possible culprits

UNR.Grad

I had forgotten to attach one of the vacuum hoses, but even after I did it went back to how it was before. There was a little improvement. I decided to switch coil pack 3 and 5 to see if the problem would follow it, but I never had time to check it again. After a month or two of driving with the light on, the hesitation has been getting worse, so I checked it and now I have codes 305 and 302. I'm thinking that it's the coil pack, but could it cause a misfire in cylinder 2 as well? 5 is linked to 2 with a coil. Let me know what you guys think, also where could I get a cheap coil pack? Just buy online or try to source a used one?

97ltd4x4

I believe you have a coil going bad....Each coil will fire both cylinders,the plug below it and the wire that attached to it....The coil actually fires both cylinders at the same time..One cylinder on compression and the other on exhaust stroke,That why the plugs are double grounded...they are being fired twice as much as a normal plug.....This also means the coil is being fired twice as much as a standard coil....So plug,wire,coil problems can be common with higher milage vehicals.

cylinders 5 and 2 share the same coil...

I replaced one a while back for a friend,I dug up the old box:
part# 90919-02213

I checked online and at 1sttyota, $67.20 not including shipping,ect

https://www.1sttoyotaparts.com/partscat.html

UNR.Grad

Thanks for the help! I'll get a new one and let you know if it takes care of the problem

audley115

I have been following this thread, as this started happening to me about 3 weeks ago. My 2002 T4R has 53000 miles on it. The roughness was very intermittent at first, but has gotten to be almost constant misfiring.

I first ran a can of injection cleaner and fuel stabilizer through the engine with no improvement. In fact it got so bad, that it finally threw off a code: P0304. Fine, #4 is misfiring. Let's switch the coil/pack to a different cylinder and see if it changes. After a week of more rough running, it threw off another P0304. So I switched the coil/pack back to the original location and took it to a mech that I trust, as I did not want to mess with injectors. He switched the injectors, and it only took 2 days of light driving to get TWO codes this time: P0300 and P0304. #4 is still misfiring, but it's also telling random/multiple cylinder misfires this time.

Any ideas?

Thanks,

Jon

98runner210

hope u don't have what happened to me. It is 6 pages long but some good info.

https://www.yotatech.com/forums/f2/c...ighway-128206/

audley115

THANKS for the link to your thread. Great information there, and I'm passing it along to my independent mech.

97ltd4x4

I would be leary of a wire if you get an even missfire code number ,p0302,p0304,p0304...If you get an odd and even code...start thinking coil pack.

Remember:The wire numbers are the coil pack location numbers,not the wire location numbers...

audley115

Completely ruled out plugs, wires, etc. Ruled out injectors. Took apart the front of the engine and found every thing as it should be. Checking the valves this weekend. ARGHH!

phosho

Same issue!
Got a miss fire on #3 code, then changed the plugs & wires. The light went away. The missing has crept back in a less pronounced fashion with no check engine light. I seem to have minimal symptoms when accelerating & on a cold engine but when I'm cruising under low rpm's at 45- 60 miles per hour (especially on inclines) I'm missing until I step on it to stop the stuttering. I am running some fuel cleaner & premium gas right now but I cant say I'm hopeful that a bottle of additive will cure it. HELP!

Has anyone got a diagnosis yet?

audley115

This is EXACTLY how my problems started.

I thought it was an ignition problem right off and told my mech (great guy) that I wanted new plugs and wires. Being a thrifty mech, he said, "Wait! That's expensive, and at your mileage you shouldn't need them. Let's check it out." So we swapped some plugs and coil packs(?) around to see if the codes changed. No joy, same code.

Next tried injectors......same code.

That's when I came to this forum and found out about timing issues with the worn Woodruff key, etc., etc. Back I went to the mech with my new found information, but he was already all over it. It had become a matter of pride with him to fix this problem! Unfortunately, (or fortunately as it turns out) there was no wear at all.

He next replaced the valve shims to get them perfectly set, but that didn't solve the problem either....ARGH!

As it had become a matter of pride, he consulted with his brother in the next town over and they found that the plugs and wires were, in fact, way out of tolerance for impedance causing the coil packs(?) to do strange things. Replaced parts and it runs perfectly now!

BTW, he only charged me for the wires, plugs & coil. It is nice to deal with honest mechs who take pride in their work!

97ltd4x4

This is becoming a problem with higher milage 4runners...And most techs don't realize that the ignition system is kinda oddball system.In that each coil pack controls two cylinders..Its kinda a in-between system..all wire system w/distrubutor..and an all coil system....

To make matters worse,unless you know Toyotas very well,the plug wiring numbering systen is messed up..In that the wire numbers are in relation to the coil pack locations on the other side of the motor..NOT where the wires go into the cylinder(driver's side)...

from front to back:
so the coil side is on the passenger side...1-3-5(odd cylinder #'s)
wires go to the drivers side...2-4-6(even cylinder #'s)

So,even side code(p0302,p0304,p0306)..need to think plug,wire,coil
Odd side code(p0301,p0303,p0305)..Need to think plug,coil..

And the coils are not sensitive to the wires,even with an open wire the coil IF good..will fire just fine...Its just that at the point of a coil going bad,most techs will want to replace the wires,because of milage...along with getting a comeback....Thats all you need to do is replace a coil(odd code)..fine for 6 months..back in shop for even code for a bad wire....

Also Because the coil is firing BOTH cylinders simutaneously,the plugs wear twice as fast..hence the double grouned plugs.

When a coil is starting to go bad,just starting to get weak,throws a code and might not feel a "miss"....eventually it starts as a slight miss under light load and might be hard to duplicate all the time,and at some point it can turn into a full blown miss,then 2 cylinders missing..shared by the two cylinders from the coil..when a wire goes bad its usually under light and heavy load,and will feel it miss on cold start up or at other times..

Another thing
that gets tricky about finding a coil going bad,is because of a weak spark either wire side or cylinder below the coil pack,is it effects that plug...so sometimes switching the coil if the coil is not completely bad,the miss will stay on that same cylinder after a coil swap...eventually it will move once that plug starts to be effected..

best thing is either to replace plugs...then swap coils to get the code/miss to move(this is best,because you will see if the plug is starting to run rich..and know for sure you are on the right track)..This is oldschool..reading plugs has become a lost art in the auto buisness..

Or swap the coil and plug at the same time...If the coil did effect the plug the miss should move now...

cackalak han

Hey, audley115, where ever I go, I'm always looking for good mechanics, as I'm sure everyone else is, too. You should post up the name of the shop and the name of the mechanic for some publicity.