Cleaning the carbon and oil blow-by in the upper portion of the intake manifold.

I can spray through the butterfly valve to clean all the black deposit as the car is running. I'm risking the contents being pulled into the engine and affecting the injectors, plugs, rings, O2 sensor.

I can pull the intake valve body off and try cleaning most of the gook while the intake manifold is on the vehicle when the car isn't running.

I'm thinking it may be wise to do the second way, cleaning as best I can while the intake manifold is still connected, but while not running the engine. Intake valve body removed, spray into the intake area, brush with a wire brush, clean with shop towels to get rid of the sticky black goo. I'm I beating myself up here?

Other components may need to be cleaned as well. I'd like to tackle the harder parts first, but without shop space or nice tools, the work on the car has to leave it running since it's the only car I've got at the moment.

 

What if any drivability problems are you having that are motivating you to do this?

 

You say: 'I can spray through the butterfly valve to clean all the black deposit as the car is running. I'm risking the contents being pulled into the engine and affecting the injectors, plugs, rings, O2 sensor.'

The injectors are not effected. Very little on the others. The worse part is your cat. It can degrade it.
My question is: Why do it?

 

Derf, I've read through past post of yours where, when you had a problem, you found it, and you fixed it. I want to do the same with hesitation, bucking, almost stalling. I'd like to have a car that rides closer to like new, and not buck or hesitate. I just want to track it down and fix it. I'm sure I'll learn something along the way. It always goes that way anyway.

It happens at freeway speeds occasionally, whether the AC is on or off. When the car is cold, it seems to happen a lot less. That's a feeling-based diagnosis.

[edited upshift to downshift] Honestly, it seems to be frustratingly and coincidentally tied to the car's need to downshift. As the downshift approaches, it can't make up its freakin' mind, so it stumbles, and pauses, and dawdles, and hesitates, and waffles, and if I just step the accelerator down to push it through the shift, it seems to finally get the kick in the **** it needs to downshift. But even after that downshift in the lower gear, whether the AC is on or off, it'll STILL hesitate a bit or buck a bit. I've had a few bad scares when I've pulled out into traffic barreling down on me but… IT… WON'T… TAKE… OFF! and my blood runs cold. Luckily the driver behind me had brakes and used them. ;-)

I wondered if the restricted air flow in the intake from the carbon and oil blow by could be a contributing culprit. That's what's got me thinnin' what I'm thinnin'.

I just bought two bottles of injector cleaner to run through two tanks of gas to see if it's something on the injector end of things. So far, there hasn't been any significant improvement after six days of injector-laden fuel.

I'm running premium fuel too, so I'm sort of doing what I can to take octane and pinging out of the equation as best I can. (Would an tank of octane booster give me any data, I'm wondering.)

I just ordered a new set of NGK plug wires. The ones currently say their make is PACKARD. I didn't buy 'em so I have no idea how old they are. The throttle position sensor TPS is new. The intake air controller IAC is new. The crankshaft position sensor CKP or CPS is brand new. The engine coolant temp sensor ECTS is brass tipped from two years go; it has not had its connector changed. I looked for corrosion, but saw none. I know it can still be a possible contributing factor. The front O2 sensor is about two years old, replaced by moi. Fuel pump is less than two years old.

I read where ping detection may come into play.
I read where a clogged CAT will cause problems and that I can test it by briefly (and loudly) removing the front O2 sensor and driving around a little. If ping goes away with the sensor removed, it points to a clogged CAT.
I read where I need to torque down the coil bolts and the PCM bolts, that loose connections can cause signal read errors.

So, lots to consider. I'm running through the last of the injector cleaner. The plug wires are next. They get delivered from RockAuto tomorrow. I'll report as I proceed and get data for the team.

 

Thank you for the details.
Now we know the why and what's been done to date.

It'll take me some time to evaluate all that.

Have any of the component changes add any effect on your particular issue or had an effect on some other aspect of performance, either positive or negative?

Also, do you mean downshift when you press the pedal down to get it to finally shift?Down?

 

I'm still waiting for the plug wire swap. The replacement parts were to replace cheap parts with top of the line replacement parts. No, they really haven't gotten rid of the hesitation and bucking I'm experiencing.

I think upshift because the RPMs increase, while the gears go down from D → 2, or from 2 → 1. So yes, downshifting.

 

They were AC Delco brand replacement plugs wires I'd bought. I replaced them today. It seems like most or all of the hesitation issues have stopped. I read where the plug cables are a carbon material, not wire. That makes sense for what I'm about to suggest.

Mechanically and physically, it makes me wonder if the old wires had developed cracks through them in spots, with segments of its internal conductor material touching face to face like flat ends of a dowel, but with non-homogeneous gaps between them - not air gaps, exactly, but yes, sort of. A pair of high resistance faces touching. Spots where there are near opens, or opens and the spark had to arc across those faces, consuming bits of power, delaying and messing up timing in the process. I'm trying to rationalize how having a set of bad plug wires would end up causing bad (down)shifting. It kind of makes sense though that the ECM would be overcompensating and working overtime if the spark weren't just right. I'll be monitoring this for the next few weeks.

I don't think there was any arcing from cable to engine block, but who am I to say. I never saw any areas on the block indicating any kind of burn from a spark repeatedly being grounded out to the same place over 10 or 15 years or more. Furthermore, the original routing kept the wires away from grounding spots.

I'm also wondering how my next MPG calc is going to go. I'm expecting a slight increase, since my spark farm has now been fully restored close to normal on each cylinder, delivered on time, full power in each spark, as originally expected and designed, and the ECM can stop working so hard.

 

Just the temperature of combustion being far enough off from the ideal design temperature and be enough to make the ignition events shall we say less than optimal. Same exact thing on my brother-in-law's 2004 RAV4. Was shifting all wonky and locking down. I suggested stock Toyota plugs. We left the original wires. Thing ran like a top.

I would have expected anything serious enough with the ignition to throw a code, but alas that is not always the case.

Glad you seem to have it figured out. For the record, stock plugs would have been my first recommendation, but you had already ordered them

 

Carbon core wires fail over time, often caused by excessive spark plug gap. It takes more kv to fire worn plugs and this higher kv runs through the wires. I have usually found the failure point on the wire is at the spark plug end. It can appear as rust on the plug connector and usually has the carbon burned back up the wire. I think I have read here that the S series engines were designed for what I would consider regular spark plugs. Not the newer exotic metal type. These plugs require more frequent replacement and have different specifications.

Back when I first started repairing cars, we tuned them every 12,000 miles. Points, plugs, condensers and wires.

 

Thanks.

It's got me to a new place I wouldn't have imagined. Plugs and wires matter? Apparently so. I believe it, but I doubt I would have been able to see it this soon. (As opposed to seeing is believing.)