Missing on Start-Up

[claydoctor]

Back in May 2013 , I took my 2006 V6 Sport with 180,000 miles to the dealer because it had started having an engine miss on start-up .It's garaged and when I would start it to leave for work , it would run rough for 10-15 seconds and then smooth out . One morning , it ran rough for about two blocks so I pulled over. Turned it off and when I re-started it , things were fine . At some point during the problem , the check engine light came on as well as the VSC OFF light and the VSC TRAC light.
I took it to the dealer . Who found a cylinder 4 misfire . They switched the coils around but couldn't get it to misfire while there . They reset the warning lights and said they suspected a head gasket starting to leak . They said they had seen this on some high mileage 4-Runners . That was on a Friday . They asked me to bring it back Monday so they could let it sit overnight and put a bore light in it the next morning . I took it home and over the weekend , the problem failed to recur even though prior to the trip to the dealer , it had been a daily occurrence .That was 10 months and 14,000 miles ago . Been running fine . Recently , the problem has recurred but not every day and so far , no warning lights.
Because of the expense involved , I am trying to convince myself it is not a head gasket . Doesn't seem like that would disappear after what the dealer did only to recur 14,00 miles later . I'm thinking a bad coil . Doubt it's bad gas as I draw from a variety of sources . Ran some Sea Foam through it . Might have helped for a day or so if any . Mass air sensor ? Dirty injectors . Hate to have the dealer replace head gasket and that not be the problem . Any ideas ?

 

[Greydog]

Change the plugs to rule them out.

But, is the code bein repeatedly thrown always for cylinder 4?

Car parts ships can pull the code you, usually for free.

If its the same cylinder each time, try replacing the injector, since you already replaced the coil.

Could be electrical connection for the injector or coil, so perhaps check those to make sure they are clean and not damaged.

Is your coolant slowly dropping in the reservoir when otherwise it was stable?

Otherwise....sounds like HG.

 

[claydoctor]

Change the plugs to rule them out.

But, is the code bein repeatedly thrown always for cylinder 4?

Car parts ships can pull the code you, usually for free.

If its the same cylinder each time, try replacing the injector, since you already replaced the coil.

Could be electrical connection for the injector or coil, so perhaps check those to make sure they are clean and not damaged.

Is your coolant slowly dropping in the reservoir when otherwise it was stable?

Otherwise....sounds like HG.

Hasn't been back to dealer to check if it's still cylinder 4 . Will try to get local mechanic to check if any cylinder is showing a miss .
What did you mean by Car parts pulling the code. You mean like a local Autozone or Advance Auto ?
Radiator was replaced 4 months ago . Presumably they filled radiator then . No coolant has been added since . If going by plastic reservoir level is reliable ,it shows about 3/4 inch ABOVE the FULL line . Went to church this morning but car has been sitting for over an hour and that's what level shows . Hope that argues against head gasket . Appreciate the help .

 

[Greydog]

Yes, Advanced or Auto Zone can pull the codes for you. It would be good to know if it's cylinder 4 each time it throws the code, or if it moved to the cylinder the ignition coil was swapped to.

Check the coolant in the reservoir when cold, mArk it with a pen, etc. check it cold every few days to a weekly, see if it's dropping slowly.

 

[claydoctor]

I plan to have the codes checked and will do the radiator tank markings . Unless head gasket leaks can come and go , I think that the length of time between symptoms and the fact that the reservoir tank still appears topped off after 4 months and 5000 miles argues against HG leak but maybe I'm whistling past the graveyard .

 

[Jeff T]

Have the light cleared and then swap the #4 coil with another. One way to rule out the coil as a problem.

Mine had a slight missfire and it ended up being the head gasket. I was really pissed as I learned Toyota "redesigned" the V6 head gasket. Common sense tells me you don't redesign something if there isn't an issue.

Good Luck!

 

[Whitebeauty]

Warm up the vehicle with the radiator cap open. Once it's been running for awhile smell the radiator. If it smells like combustion ie. Exhaust fumes or n e thing other than the smell of sweet coolant it's the HG.

 

[claydoctor]

Coolant level is not changing . Really weird . Sometimes misses just for few seconds and straightens right out . Other times will continue missing for several miles until I get tired of it , pull over, turn key off, turn it back on and it is fine .
Check engine light and other light are currently on but in the last few weeks have come on only to go off for days and then come back on . Had local mechanic check codes "misfire cylinder 6" also showing code for" random misfires". I have iridium plugs but they have 60,000 miles on them . Plan is , I'm going to change plugs and coil on cylinder 6 (back cylinder driver's side , I believe). Been on parts sites looking for coil and see "ignition coil" vs "direct ignition coil" . Direct is more expensive, both Denso . Confused by that ???

 

[radlynx]

if after changing the ignition coil with another one on cylinder 6, it still does it then try swapping the fuel injector. it could be an injector too. keep us posted.

Coolant level is not changing . Really weird . Sometimes misses just for few seconds and straightens right out . Other times will continue missing for several miles until I get tired of it , pull over, turn key off, turn it back on and it is fine .
Check engine light and other light are currently on but in the last few weeks have come on only to go off for days and then come back on . Had local mechanic check codes "misfire cylinder 6" also showing code for" random misfires". I have iridium plugs but they have 60,000 miles on them . Plan is , I'm going to change plugs and coil on cylinder 6 (back cylinder driver's side , I believe). Been on parts sites looking for coil and see "ignition coil" vs "direct ignition coil" . Direct is more expensive, both Denso . Confused by that ???

 

[claydoctor]

Waiting on parts . Plan to change all six plugs and the three coils on driver's side .

 

[Kmvreter]

Waiting on parts . Plan to change all six plugs and the three coils on driver's side .

Why not just swap coils around to see if the problem follows? Driver to passenger side. Or did you already do this?

 

[claydoctor]

Why not just swap coils around to see if the problem follows? Driver to passenger side. Or did you already do this?

Eight months ago they said it was missing on 4 and they switched coils . Now they say it's missing on 6 . Both are on driver side , the hardest side to get to . I suspect if it's coils they switched the #4 coil to number 6 position
Easier for me to just replace all coils on left side and all 6 plugs since they are at 60,000+ . If I switch coils to other side and it still misses , I have to get someone to check codes again go through replacing coils again on passenger side .
I think my way is more likely to fix problem with least amount of hassle . If it doesn't I can always change coils on easier side.

 

[radlynx]

keep us posted. i'm interested to know what fixes this.

Eight months ago they said it was missing on 4 and they switched coils . Now they say it's missing on 6 . Both are on driver side , the hardest side to get to . I suspect if it's coils they switched the #4 coil to number 6 position
Easier for me to just replace all coils on left side and all 6 plugs since they are at 60,000+ . If I switch coils to other side and it still misses , I have to get someone to check codes again go through replacing coils again on passenger side .
I think my way is more likely to fix problem with least amount of hassle . If it doesn't I can always change coils on easier side.

 

[claydoctor]

For the past 3-4 days it has been smooth as a babies butt on start up and the warning lights have once again turned themselves off . It's as if it knows I have just dropped $200 on parts and it's toying with me .:dammit:

 

[claydoctor]

OK . It's done . Changed all 6 plugs with NGK iridiums and replaced the three coils on the driver's side with new Densos . Good news is I found no evidence of coolant on any of the plugs . Several of the plugs were a bear to remove.
They broke loose OK but very hard to unscrew even though I had put non-seize grease on them last time . Felt like you were going to wrench something off . Last plug was the worst naturally. Shot PB Blaster in on top of the plug and left it overnight . Didn't phase it ! Just have to take it slow .
Started up and runs smooth with no lights but then it's been running smooth with no lights for the last 4-5 days ?? We'll see .

 

[radlynx]

Looks to me it's one of the ignition coils. now you have an extra coils for later use.

OK . It's done . Changed all 6 plugs with NGK iridiums and replaced the three coils on the driver's side with new Densos . Good news is I found no evidence of coolant on any of the plugs . Several of the plugs were a bear to remove.
They broke loose OK but very hard to unscrew even though I had put non-seize grease on them last time . Felt like you were going to wrench something off . Last plug was the worst naturally. Shot PB Blaster in on top of the plug and left it overnight . Didn't phase it ! Just have to take it slow .
Started up and runs smooth with no lights but then it's been running smooth with no lights for the last 4-5 days ?? We'll see .

 

[claydoctor]

Looks to me it's one of the ignition coils. now you have an extra coils for later use.

That was part of the plan. BTW, shopping for coils on the internet is really confusing . Many of these parts sites make it even more so . One had two different coils with two different prices and the same order number .Toyota Dealer wanted $129 per coil . I bought OEM Densos online for $56 a piece .

 

[claydoctor]

Well , it's been ten days and 500 miles or more . Still running fine but I'm afraid it may be suckering me . At 195,000 miles and the aforementioned problem , I was beginning to think it was time for a new vehicle but I can't find one that grabs me . Do not care for the current generation 4-Runner. The new Highlander looks worse than previous model and gas mileage no better than my 4_runner . Even looked at Jeep Cherokee but it has less cargo space than my wife's Mazda CX-5 .I thought I was going with the Subaru Outback until my wife decided the seats were too short, front to back and if momma ain't happy, ain't nobody happy !
I have just about decided that I will keep it but it needs shocks . You may remember that as soon as I ordered new plugs and coils, the miss went away and the warning light went out. I'm now afraid that as soon as I order new shocks, the miss will return .hwell:

 

[radlynx]

trust me, it was just the coils. don't be paranoid. at 195000 miles, you are just due for coil replacement. i have 95000 miles on my car and the coils has never been replaced. i recently replaced the radiator though since it started leaking. by the way, i already replaced my rear shock but the front is still good. at least you don't have any monthly car payments. :cheers:

Well , it's been ten days and 500 miles or more . Still running fine but I'm afraid it may be suckering me . At 195,000 miles and the aforementioned problem , I was beginning to think it was time for a new vehicle but I can't find one that grabs me . Do not care for the current generation 4-Runner. The new Highlander looks worse than previous model and gas mileage no better than my 4_runner . Even looked at Jeep Cherokee but it has less cargo space than my wife's Mazda CX-5 .I thought I was going with the Subaru Outback until my wife decided the seats were too short, front to back and if momma ain't happy, ain't nobody happy !
I have just about decided that I will keep it but it needs shocks . You may remember that as soon as I ordered new plugs and coils, the miss went away and the warning light went out. I'm now afraid that as soon as I order new shocks, the miss will return .hwell:

 

[radlynx]

you have to remember, you only have 1 bad coil. so you have 2 spares. if for any chance this happens to the passenger side, you can use that spare for testing. hopefully you remember which one of the 3 spares is bad. keep 2in your car so that if you need to go for a long drive and this happens, you can just swap one out. i know for sure the other 3 at some point will fail in a couple of months.

have to remember, when 1 coil starts to fail all the rest will fail at some point maybe in months or years. so what I usually do is replace the whole thing all at the same time. at 195000 miles, your car needs a TLC.

Well , it's been ten days and 500 miles or more . Still running fine but I'm afraid it may be suckering me . At 195,000 miles and the aforementioned problem , I was beginning to think it was time for a new vehicle but I can't find one that grabs me . Do not care for the current generation 4-Runner. The new Highlander looks worse than previous model and gas mileage no better than my 4_runner . Even looked at Jeep Cherokee but it has less cargo space than my wife's Mazda CX-5 .I thought I was going with the Subaru Outback until my wife decided the seats were too short, front to back and if momma ain't happy, ain't nobody happy !
I have just about decided that I will keep it but it needs shocks . You may remember that as soon as I ordered new plugs and coils, the miss went away and the warning light went out. I'm now afraid that as soon as I order new shocks, the miss will return .hwell: