Glowing red hot manifold on 2001 Sienna

[SiennaJay]

Thanks very much in advance for any help an advice. I am new. I've read everything I could find here on this problem before asking this.

I've got 2001 Toyota Sienna, 155K with a glowing red hot exhaust manifold as well as codes for misfires on cyls 2,4,6 & 1 (#1 only recently appeared; 2,4,6 have always been there since CEL appeared over a month ago). Plus code P1354 (VVT system bank 2). Mechanic replaced plugs and switched out front 3 ignition coils. No change. 1/2 tank fuel w/ STP fuel injector cleaner so far. No change.

It's not actually the manifold glowing, it's the 5" or so exhaust "chamber" that the upstream A/F sensor is plugged into, between the exhaust manifold and the exhaust pipe going to under the engine. The exhaust "chamber" for the rear three cylinders, under the engine, is not glowing red hot.

Toyota recommended first checking for sludge and doing a spark test on front cyls 2,4,6, which I'll do tomorrow. My guess is all is fine there.

Next they said would be to check fuel pressure at idle and on the road. I'd have to have my mechanic (a Toyota-only guy) do that. Maybe fuel filter; maybe fuel pump, they say, then on from there if not, with unknown $ and time to eventually find/fix the problem.

One forum person found a cracked air intake hose which solved the identical problem (including same codes), but mine hose looks okay. I have a car-knowledgable friend who may be able to help me check for vacuum leaks if needed. (I read here about spraying water or I believe carb cleaner or starter fluid around the intake system to see if idle goes down or up, respectively.)

From what I read here, car is probably running lean from either too much air, or too little fuel. I see suggestions about the oil control valve being the potential problem and am trying to learn about that (Haynes manual), although probably beyond my ability to check/repair.

The car always accelerates fine. Plenty of power during acceleration. To me, there seems no lack of fuel supply.

The engine idles high until warm, beginning at about 1800 rpm and gradually going down to the normal 800 rpm. Previously, it's normally been at around 800 all the time. The engine seems to run smooth when idled up, and only a little rough at regular idle, but the "chamber" still turns red hot without the car ever moving.

When on the road at constant speed, with the car is neither accelerating or decelerating, the engine will suddenly lose power, then after a second, it picks back up. If I work to hold hold the "no acceleration or deceleration" business (like going slightly downhill so my speed is constant with with no engine work), there is this pattern -- 3 secs good, 1 sec loss of power.

Here's something strange: When the car is in motion, rolling in neutral at anything over about 1mph, the engine will cut out every three seconds when I try to hold a constant rpm above 2200. I tested this strangeness at 6K, 5K, 4K, 3K, 2400, 2000, 1800 rpm. I can hold the rpm constant and smooth for only just over 3 seconds, then there's a drop in rpm of about 1/3 (about 1800 at 6000 rpm), then the engine picks back and runs fine for 3 seconds. This pattern repeats precisely, like clockwork. At 2000 rpm and below, it doesn't matter if the car's moving or not - the rpm always hold fine and smooth. When the car is in NOT moving, in park, I can hold the rpm at any engine speed with no problem, so it's only when the car is moving that the engine cuts out every three seconds. It's the same pattern as when holding the "no acceleration or deceleration" thing when in drive.

Consensus in the forum elsewhere seems to be that if it were a plugged up cat, I wouldn't be getting high rpm just fine. (My mechanic suggested a clogged cat as a possibility.) Also, it seems to me that the "chamber" for the rear three cylinders might be getting red hot too.

Oil change was suggested. I'll do that tomorrow.

The CEL blinks sometimes when I'm at a red light, but if I slide it into neutral and run about 2000 rpm, the CEL goes back to steady after a few seconds. Not sure what this means and am just noting it.

What should I have my mechanic do 1st, 2nd, 3rd? What can I do myself or with the help of someone who is much more car-knowledgable than I am?

There seems to be a long list of possibilities and possible big $ from Toyota. I'm not sure how much the tech listened to my info. I got the feeling he read the codes and said "here's the procedure of things to check". I can't afford to keep replacing/checking everything until something finally fixes the problem (or doesn't)!

I'm sorry to be so long; just trying to provide all the info I can. Thanks very much again for any help.

[Nark]

I was experimenting with my 22re truck by closing off EGR inlet valve. Boy, that thing get hot really fast. You can smell the exhaust metal and sizzling. For some reason I could do it to my older Chevy.
As for clogged cat converter...I'd 80% clogged on my current Cressida and I don't have much problem driving at high speed. I thought it would reduce top end but that not so much true. Mine did not shown any significant heat like your though. Of course, once a new cat got put in it run much better.

[csaxon]

P1354 is cause of all your problems. You need a competent mechanic.

[SiennaJay]

Thanks. My mechanic has worked on Toyotas for decades (worked for Toyota 20 years). He always does a good job, but how good he is at troubleshooting, I don't know.

No sludge. Spark tests on front 3 (problem) cylinders were fine. Tried spraying starting fluid around the intake areas to check for leaks and didn't get any increase in idle. Changed the oil just because it was time to.

[csaxon]

P1354 is cause of all your problems. You need a competent mechanic.

[Bdub215]

Originally Posted by csaxon

P1354 is cause of all your problems. You need a competent mechanic.

yah i agree. i couldnt tell you if its the VVT gear itself thats bad, the OCV screen for that bank being clogged causing the gear not to actuate, or the OCV itself is faulty. but its one of those three i'd bet.

[Nark]

Premature opening of exhaust valve can definitely causes a missed fire so VVT stuck on advance make sense. I'd get it fix fast because you can burn up cat converter, O2 sensor and cause even more CEL and money.

[SiennaJay]

Thanks. Have an appt with a different Toyota dealer tomorrow, with a mechanic who was highly recommended.

Get this -- last night for one solid hour, everything was fine. Knew right off something was better. I even took it out and made the engine work hard for 25 mins. Got home, no glowing at all. This morning - trouble is back.

In six weeks, this is the first time the problem has "disappeared" - so it's something that can "disappear" and reappear.

Wish me luck at the different dealer Thanks for the suggestions.

[SiennaJay]

It ended up being the VVT gear.

They (Toyota dealer) ordered the part, but I don't think they put it in. Cost was all labor (about $500) I think they just "unstuck" the gear and did whatever was needed to make sure it will continue to operate properly. Runs great.

Thanks for the help!