hatda02

Hey all.

I picked up my 99 Highlander back in Nov. from a guy who had it posted here and also the PGH Craigslist. It has a 130k and although I was looking for something around 50 to 70k I bit because I REALLY wanted the 5 speed with the sport hood. And for 8 grand it already had basically the same suspension work I would have done so that probably saved a few grand and a lot of cussing.

The PO pointed out two problems. One was sometimes it did not want to go into second and a 'clunk' sound from the rear.

Well I think the tranny problem may have been user error because it has never happened. I would hear the 'clunk' sound at times and figured someone f'd something up when doing the suspension. I was really going to tear into in when it warmed up.

Last weekend I took it to get inspected and on my way home it started stumbling at low RPM and finally threw a CEL. The funny (not really) thing was the 'clunking' that sounded like it came from the rear was happening more and seemed to be in sync with the stumbling. I took it to ghetto zone and they said it was random misfire P0300. The engine has serious power loss when it stumbles/'clunks'.

I read every tread here with either misfire or P0300 in it and I REALLY think it is the same as those who had a torque problem on their crank pulley. I think this because it makes sense and is my dumb luck.

In some of those threads people would say they would troubleshoot a random misfire differently than they would those who had a particular cylinder misfire to go with the random. So what I am looking for is a little insight trouble shooting wise.

First off it has a timing belt sticker done at 96k. Other than that I have NO maintenance history. So I need to do it all. So this lends to fixing my problem along with doing all the maintenance:

1. I replaced the fuel filter last night, but have not bothered running it. I doubt this is the problem.
2. I replaced the plugs and found the plug seals are shot and some oil is getting into the tube. So this this means I'll have to rip the valve covers off.

So....in some of the threads where they talked about the loose crank pulley it was said to hook an o-scope to the crank sensor and look for funny patterns. I don't have an o-scope. Shoud I be able to start the truck and see it wobbling in there if it is loose? The stumble does not happen unless the truck is under load; it is fine idleing or reving while parked.

Any other ways besides visually seeing if it is wobbling to tell if this is my problem?

I'm going to do some other things in the next week or so like flushing the coolant, cleaning the MAF sensor, cleaning the throttle body, new wires, tranny/xfer/diffs/clutch fluid, PCV, and grease everything. And I'm doing those seals for the spark plug tubes and the valve covers (intake too) because of the previously mentioned leak.

So really I'm looking for some insight into my problem but wanted to give a run down of what I'm planning in case someone has other suggestions while I'm working on a certain area or maybe tell me to do something in a certain order.

mt_goat

Try putting a socket on the crank bolt and at least see if its finger tight or if you can tighten it at all with the socket wrench.

hatda02

Thanks. I gave that a try and the motor turns so it is at least somewhat tight.

98runner210

pull off your upper timing cover have someone move the crank back and forth and make sure your cams are moving at the same time without any play. this will rule out the loose crank/worn crank gear

vital22re

iTrader: (2)

if you're getting oil down into the spark plugs and its getting betweent the boot and plug it will cause a random misfire i've seen it so many times! make sure you clean the plugs and boots for the coil over plugs that you should have.

hatda02

Thanks for the advice. I will give the first recommendation a try today.

As for the oil....STUPID me. When I pulled the old plugs out I cleaned out the tubes and put new plugs in, but I did not clean any of the boots. This very well could be it too. I'm going to order the seals/gaskets this week along with new wires. When I rip everything out I will make sure I clean the coil boots since the other boots will be new.

I'll report back in a week with an update.

Thanks again.