After washing engine, engine hesitates at acceleration

2004 Sequoia SR5, RWD
211,000 miles.
Owned since 45K miles

I decided to wash the engine yesterday as it was pretty dirty with grime and what not. Used Gunk engine degreaser, various brushes and used water hose to rinse clean. I did not cover any components.

After washing, I let it dry in direct sun for about 30 mins (it's been hot out here in SoCal). I drove the car around for 10-15 mins and all was well. No issues.

Today, my wife took it out driving and engine started hesitating on her during acceleration. Engine did not stall or die, only hesitates during acceleration. CEL is on as well as the VSB and traction light. These lights have come on in the past over many years and I remove neg lead from battery and reinstall and it usually clears all of these lights. I did it just now and lights were cleared but hesitation still persists.

What could have caused this issue?
I hesitate to drive it to Auto Zone to have it tested on their OBDII scanner, as it may stall out?

Thoughts on what it might be?

Thanks

 

Check you vacuum lines. You may have inadvertently popped one off. Also, you need to to a proper throttle body cleaning after disconnecting the battery as it has to go through an idle relearn procedure. Get a can of Throttle Body Cleaner and a rag. Disconnect the negative battery cable for 10 minutes, spray the cleaner into a rag (never into the throttle body directly), and wipe all buildup away. Gently lift the throttle plate and clean the edges and around the inside. Don't let the throttle plate slam shut. Reinstall the negative battery cable after - you're removing power so the ECU is forced to re-learn, and it will return to baseline running parameters.

 

Made it to Auto Zone. On the way, hesitation cleared and now its running smooth again! The code is P0308, Cylinder 8 misfire detected.
I am assuming there may have been residual water in the coil pack, however, with the heat here at over 100F everyday, and driving it till it reaches temp, I would have have thought it would be dry to the bone.

Is the code stored for a period of time? Because when it was scanned at Auto Zone, there was no hesitation (hesitation was gone several miles before getting to AZ) or check engine light on.

Where exactly shall I wiper away on the throttle body, as I have never done it on this sequoia? Do I disassemble the air intake?

Since the hesitation is gone, do I need to still do this?

Thanks

 

This happened previously with my Lexus gs400 even though it’s not a sequoia. I had my engine bay detailed bad idea! Especially without the car running. I had multiple misfires hesitation obviously cause it wasn’t running on all cylinder's. I let it sit for a few days cleared the codes hesitation went away. A lot of guys used compressed air water will get into the coil packs and spark plugs I’ve read guys used rags or vacuums to get the water out or changing out the plugs. Hope this helps but I will never get my engine bay detailed with water lessson learned for me!

 

My dad would always tell me when you wash your engine always do it cold. And you need to hit it with compressed air around the coil packs and spark tubes or water will get in and cause some issues. Probably what happen here

always use a power washer and not the hose directly.

next time you change your spark plugs you will see the coil boots will be all brown.

 

Yes, Until the ECM commands the IM monitors to perform a test, usually within a few drive cycles.

Here is a diagram. You'll remove the hose from the air box to the throttle body and inside you'll see the butterfly. It'll be obvious once you see it.

 

Does the Throttle Body need to be removed from engine to be cleaned or can it be cleaned while still attached to engine?

 

Easier if you remove it but it has two coolant lines and a couple electrical connectors that may break. Gasket may need replacement if it’s been on a long time. You can do it with TB on vehicle remove plastic intake duct. Hold throttle blade open with your hand or plastic utensil ( don’t use metal object and don’t let it snap closed. Spray TB cleaner on a rag and rub the blade and the aluminum bore clean. It will take a little bit of elbow grease. There are some good YouTube videos. When finished remove negative battery terminal for a few minutes to force ECM relearn. You will have to re-do your radio presets and clock time

 

Do it on the vehicle. No need to create more work.