mendy74

Need some assistance. I have a 2000 es 300 with 192K miles. Car has some hesitation for a about a week or so and this morning check engine and had misfires on 1,3,5. So put in new plugs, used MAF spray to clean the MAF and throttle body cleaner to clean the throttle body. On the firewall plugs they were had oil on the threads of the plug by the way. Changed them out started it up idle seemed a little high, but ran like a top for about 20 miles around town and then hesitation came back noticeably around 40 MPH staying on the throttle. No check engine yet from any misfire but same hesitation that it started with before. Saw on another thread potentially could be due to oil leaking in from the valve cover gasket? Any assistance if this is the next step and to help understand why this would cause the misfire and hesitation if its from the top of the valve cover. Is it leaking in from the three oil seals where the spark plug channel is on the valve cover? The top of the plugs didn't have oil on them just the threads as I took the plugs out.

Any way, thanks to whoever can assist.

2GSKaizen

iTrader: (1)

I think it sounds like the valve cover. The seal gets cracked where the valve cover seals to the metal tube that houses the spark plug. The boots from the coil packs cover the top of the plug, so it never gets any oil on it. I have seen some where the spark plug tube fills with oil, and gets the spark plug boot wet. The boot then gets rotten, and allows the spark to jump out of the side of the plug boot, causing a misfire. Did the front three plugs have any oil on them? Did any of the spark plug boots look like they were wet with oil?

mendy74

Thanks for the reply. No the front plugs no oil. If your facing the engine not sure if its 1 or 5 cylinder head plug had the most with some oil on the coil rubber. So probably the cover then. Any difference in the gaskets I was just looking at them they had beck/arnley and Fel Pro?

Thanks again

2GSKaizen

iTrader: (1)

If you plan on keeping the car for a while, spend the extra $20 and get the gasket from Toyota dealer.

mendy74

The plug gaskets are about 40 bucks and gaskets from lexus were around 22 each. So just get all the gaskets from lexus then is what I am hearing.

Thanks again

mendy74

Update, so I went straight to lexus, replaced the valve cover gaskets, seals around spark plug tubes, tossed everything back together, ran great for two days back and forth to the kids school which is about 20 miles round trip. This morning check engine again, same symptoms of the rough idle again. I haven't pulled out the plug closest to the driver wheel I think its 5 cylinder due to just got back and figured would wait until the engine cools before pulling the plug and checking again if there is oil in the tube.

What else would lead to oil in that tube or on the coil/plug?

Thanks again for any assistance,

BDSL

If you have a CEL, get it scanned and let us know what the code is.

mendy74

Ok pulled all plugs dry as can be, looks like one of the vacuum hoses has a crack in it and I one of the vacuum sensors didn't latch since the tab was broken, zip tied it on to keep tight, definitely less of a hesitation. Would that line potentially cause the hesitation like that? I will run grab some new tubes.

Also on another note noticed there looks to be some oil on the timing cover seam if your facing the passenger tire the right hand side of the engine. I haven't searched the forum yet but figured I would ask.

Thanks again,

Hayk

iTrader: (1)

Scan the CEL code, fix the vacuum leak and report back. The oil leak by the valve cover is mostly likely a bad camshaft seal, very common problem.

mendy74

Ok will do, thanks.

Any video's/tutorial on camshaft seal replacement?

mendy74

Ok so got the code pulled P0303
Cylinder 3 misfire.

Should I redo all the hardened vacuum lines to start? Of course after they pulled the code I went in to grab the printout. Got in the car and started it and no check engine light now.

Hayk

iTrader: (1)

Cylinder 3 is the middle one by the firewall, if I recall correctly.

Camshaft seals require the removal of the timing belt - extensive job.

mendy74

So I thought I figured out what the problem was. The line from the vacuum switch to the plenum part number 90447-08150 on Sewell Lexus. This line was cracked and I replaced it with one from Orielly auto. So this line didn't fit snug. I took a piece of black tape spliced it to make the tube the lines ran from the switch to the piece on the back of the plenum. Put the line back on.......check engine gone and it ran fine. Ran out to the store with our other car, figured let me start it up and see what it does, started up and the RPM's went up and down between 1500-2500 about 10x. I just shut it off. Do these vacuum lines have to be the dealer, looking at the new one I got and the same size line from the one that was cracked they appear to be a little smaller. If so this is 20 bucks a foot at the dealer for that piece. As the RPM's fluctuated the check engine light did not come on.

Thanks again.

LeX2K

You can order generic vacuum hoses from Toyota here's a chart just pick the length. You can swap over the plastic protector from the original hose.

mendy74

To recap, had oil in spark plugs changed the valve/tube gaskets, after I was done idle was rough triggered cylinder 3 misfire. The vacuum line I replaced going behind to the back of the plenum was too large due to from autoparts store needed OEM. Thanks to forum, Toyota dealership hooked me up with the tube, put it on, I also swapped the coil in cylinder three with the front side of motor to cylinder 4 to see if the misfire would jump. Car ran fine for two days probably around 50 miles, then started the rough idle again and when I came to a stop yesterday brake pedal depressed all the way and had to pump it. This happened two times during the rough idle. I went over to pull the codes this morning started the car had same rough idle for about 10 seconds then kicked into a high rpm at around 2K, idled down as it warmed up then ran fine to the autoparts store they pulled the code and no misfire code but triggered a P1349.

Any assistance would be great thanks again.