'99 SR5 V6 with 165,000 miles. Just replaced spark plugs, plug wires, PCV valve/grommet, air filter and fuel filter. Started with those items, because my T4R needed them anyway, and I was hoping my problem would go away in the process. It didn't.

Every few days, when I crank it up cold in the morning, it idles pretty roughly. Stumbles and sounds like it's going to die. I start driving to work, and it clears up. Runs fine for at least several days, then does it again. It was doing this before I changed the plugs, wires and filters. Does it on 10% ethanol gas, and gas w/o ethanol.

Any thoughts on where else I should start investigating?

Any white smoke on start up?

Could try cleaning the MAF, perhaps?

Checked for vacuum leaks at all?

Come to think of it, yep - a little white smoke on startup. I'll look into cleaning the MAF. Typically, I buy 10-20' of vacuum line and replace it all under the hood when a vehicle has some miles on it. Don't think I've done that yet to this one. Cleaning the MAF and replacing vacuum lines are things I should do anyway.

Thanks.

Aside from the drive shaft u-joints and starter contacts going out, this has been one of the best, most reliable vehicle I have owned. Wellllllll, except for the Miata I had for 7 years. That one took the cake on being dead-nuts reliable. Now, if I could just devise a way to change the oil on this T4R without it being a PITA and dripping lots of oil, I'll really like this thing.

I don't want to say it's the issue, but it could possibly be the beginnings of a failing head gasket? I'm not a mechanic by any means, I have heard of similar things though...


This should help with that...

what kind of spark plugs are you using. hopefully is not bosch .

NGK BKR5EKB-11's.

Ruh roh on the head gasket. I imagine that is a very major task, despite me having about 10 timing belt jobs on various vehicles under my belt. Anyone reading this replaced a head gasket?

check your coolant reservoir level. make sure its not empty , its possible coolant is sipping out overnight from headgasket and going to your cylinder . this will cause hardstart in the morning, did you check you old plugs colors, redish white it might be coolant in cylinder , dark or sludge possible oil/bad gas. this will cause misfire tho if your headgasket is going bad. try cleaning your mass air flow sensor and throttle body first . and let us know. gl

That's it. It's a head gasket. Plugs were reddish white. Added some coolant a while back. I imagine a head gasket replacement isn't a weekend job. This is my only vehicle, and I can't afford to pay a mechanic, so it's going up for sale soon.