gap81

Posted this problem a few weeks ago and just thought I'd post the solution for those who asked me to.

I tested everything to no avail. MAF, IACV, every sensor I could find all tested fine. Truck ran fine except when I'd come to a stop. Finally took it to my mechanic. He had it for a week and couldn't figure it out. He tested everything I did and all of it checked out. We were looking at the engine as he was explaining how pissed he was that he couldn't find the problem and he noticed a thread dangling from the timing belt(just changed 15k ago).

I've never been this deep into this engine so I hope I explain this right and please correct me if I'm wrong.

As I understand his explanation, the Woodruff key which holds the crankshaft pulley or dampener in place had broken, not all the way but just the part that juts out into the "keyway", but it was just enough that the pulley worked its way out a little. This caused the belt to be slightly out of line with this bottom pulley(explaining the rub on the belt and dangling thread). This caused the random misfires.

New Woodruff Key and alignment of the pulley/dampener and the misfires and stalling are gone. I had to pay for what was probably an unnecessary new crank sensor but I was ok with that considering I never would have figured this problem out on my own. I was grateful that he didn't just start throwing parts at it. It cost me a few hundred bucks but I thought it would be more than that.

He said he had no idea how that happens but he saw it once before on an old Supra so he took a shot. Hopefully this thread will help somebody else.

DoubleZero4x4

That is very nice information to have. The really god part is you got your truck back in good running condition and you didn't have to fork out too much. I will certainly file that one away for future reference.

khaug

This can happen if the crank pulley is removed to change the timing belt and not torqued properly when it's replaced. The torque spec for the crank pulley is HUGE, like 225 lb/ft or so (don't use this figure), and can't be attained without a Toyota special tool to hold the crankshaft while the bolt is tightened. The pulley will eventually loosen and damage the key if not torqued properly. You're lucky the keyway on the crankshaft wasn't damaged, as often happens, as the fix for that is a new crankshaft.

If the repair wasn't done by a dealer with the special tool, I'd want to ask some questions of the shop that did the job, like how much torque did they use for the crank pulley bolt and how did they hold the crank when they tightened it. You sure don't want this to happen again.

Good luck.

gap81

That is very good information. Repair was not done at the dealer and the timing belt was changed by the same shop about 15-20k ago. I'll pass this along to them. They work on all makes and models so this is info they may not have, and I'm sure they would be interested in. Thanks.

Tragic Drive

Thanks for the follow up thread good info here
,Thomas