misfires first 30 seconds cold start

[tlpsound]

04 Toyota SR5 sport 4 runner runs rough for about 30 seconds from cold start. After that it runs fine. Engine, and VSC lights are on.
Computer said cylinder 6 is misfiring.
I changed spark plugs and ignition coil on cylinder 6.
Lights went off, and I thought it was fixed. After about a week it is back with the same problem.
Any suggestions.
Thanks

 

[ebg18t]

Head gasket

 

[peebee]

It sucks, but I'd have to agree with ebg18t. Do a leak down test.

 

[Calimander]

ditto head gasket

 

[tlpsound]

sounds like a good time to get a new ride

Sounds like it is time for a new ride. My other Toyotas have done much better in the past. I don't remember doing any major repairs at 115k on any of my vehicles.
Thanks

 

[Pirate VI]

How do you do a leak down test? I have the same problem, but with cylinder #2. Also new plugs and swapped around coil packs.

 

[NJshadow93]

Sounds like it is time for a new ride. My other Toyotas have done much better in the past. I don't remember doing any major repairs at 115k on any of my vehicles.
Thanks

The V6 that came in the '03-'05 4Runners (but for whatever reason, seems that 90% of the failures are '04) has a poorly designed head gasket that seems to be a common point of failure as these trucks age. Toyota did redesign it at some point ('05 or '06) and the new design seems to be fine. If you were to get it fixed it's not something that should happen again (unless it's overheated, but that's the case with any aluminum engine)

 

[tlpsound]

what else should I replace at the same time

I am taking it to a local mechanic. Should other things be replaced at the same time, like water pump, and belt? What about timing chain?

Thanks for all the help. I guess I am going to get it fixed, still cheaper than a new vehicle.
Thanks

 

[peebee]

How do you do a leak down test? I have the same problem, but with cylinder #2. Also new plugs and swapped around coil packs.

Tons of instructions and videos online. Just search google and youtube. They'd explain it much better than I could anyhow.

 

[tlpsound]

not HG

I took it in to a shop, and thank god it was not the HG. The coil I had replaced a little over a week ago went bad in one week. Lesson learned buy Toyota parts.
Thanks for all the help.

 

[peebee]

That's good news. Glad it worked out well for you.

 

[ebg18t]

I took it in to a shop, and thank god it was not the HG. The coil I had replaced a little over a week ago went bad in one week. Lesson learned buy Toyota parts.
Thanks for all the help.

Give it a couple weeks. Many people have replaced coils and the problem reared its head again a few weeks later. Hopefully yours is just the coil.

 

[Calimander]

I'll wager 5to1 that his coil(s) are just fine. A lot of us went through similar scenarios till we got the head gasket replaced. Let her sit and scope #6 for coolant.

 

[tlpsound]

It is back Compression is over 160. Do you still think HG?

 

[NJshadow93]

It is back Compression is over 160. Do you still think HG?

Yes, if a compression test doesn't show it a leak-down test probably would. But unfortunately it's a pretty safe assumption to say it's the HG.

 

[ebg18t]

It is back Compression is over 160. Do you still think HG?

I was afraid you would be back. Unfortunately this happens and shops try to get you back out the door with a 'reasonable' fix. But on this motor it is usually the HG. Sorry