[Klove]

Hi my name is Kendra I have 2001 Toyota Avalon. So I've noticed lately it's been idling a little rough and running a lil sluggish .RPM seem to drop a little when I have it in park or coming to a stop and then jump back up. When coming to a stop it also seems to become a lil Shakey and feels as if it's gonna die but doesn't (take take that back and has died twice but starts back up) I take very good care of the car I have regular oil changes done . All new tires brand new brakes and rotors. Changed all struts and a few other things have . I recently changed spark plugs ,new battery I have also some emmison work done doing to not passing smog last year. My check engine light is not on. so my question is can my engine coils be bad and have no check engine light? I've been going crazy trying to find the issue with my car without spending too much money. Is there anyone out there that may have an idea I'm what it could be?

 

[Bigplanz]

Cheap things to try: clean the throttle body and clean the MAF sensor. Idle air control valve could also be bad/dirty. My wife's Ford had the same symptons and would die at stop lights. MAF sensor readings were bouncing all over the place. Put a new one in and that fixed it.

 

[vibeusa]

What you are describing is symptomatic of a dirty IAC (idle air control) valve and/or throttle body.

If you have changed the air filter (the one in the engine bay and not the one located at the blower motor behind the glove box), your next step is to take out the air intake boot (disconnect it from the filter housing assembly and throttle body) and spray a bit of MAF sensor cleaner or intake manifold cleaner behind the baffles of the throttle body.

 

[Klove]

1. Ok thank u both will give these things a try. So I was also doing some reading and it says something about the ignition coil.do any of you know if the check engine light comes on if your ignition coils are bad? I did recently change all spark plugs.

 

[Klove]

I was also reading about the VVT solenoid anybody know if thats a simple fix?

 

[vibeusa]

1. Ok thank u both will give these things a try. So I was also doing some reading and it says something about the ignition coil.do any of you know if the check engine light comes on if your ignition coils are bad? I did recently change all spark plugs.

Np.

Yes, a CEL will light up if there is a misfire. Could be caused by a defective spark plug and/or ignition coil. Make sure the ground wires are not rusted or loose.

I was also reading about the VVT solenoid anybody know if thats a simple fix?

In Toyota's literature, it's called the camshaft timing oil control valve. Both solenoids are on the right side of the engine (when looking into the engine bay). One of them is right next to the bank 2 senor 1 oxygen sensor connector. Should not be too hard to locate.

 

[Klove]

Ok thank u for the response. Anyone know of a honest mechanic in Sacramento CA? I'm beyond frustrated trying to figure out what's going on . Spending money on doing unnecessary things and still didn't fix the problem. I may just be time to take it to get diagnostic.

 

[abacus32]

Ok thank u for the response. Anyone know of a honest mechanic in Sacramento CA? I'm beyond frustrated trying to figure out what's going on . Spending money on doing unnecessary things and still didn't fix the problem. I may just be time to take it to get diagnostic.

Kendra, in all likelihood your Avalon (a 2001 like mine) needs an exhaustive cleaning/degreasing of the valve covers, intake plenum, idle air control, MAF sensor, and egr system. I didn't trust a mechanic to be thorough and so did mine myself this Fall using Super Clean, CRC Throttle Body Cleaner and MAF cleaner (Walmart). It took all day, but all idle problems disappeared immediately. Afterwards, switching to a high detergent full synthetic engine oil (Pennzoil Platinum High Mileage 5W30 every 7K) and I'll never have to go through that again.

While you're there, check and replace any egr/vacuum lines that have become hard and brittle.

Don't spend money on replacing ignition coils or VVT solenoids unless a CEL light indicates a malfunction.

In retrospect, and as stated earlier the idle air control and the throttle body were so gummed up with sticky Dino oil residue that degreasing the inside of the valve covers was OCD and could've waited until the 100K Aisin Water Pump/Timing Belt change interval.