toyota with rough idle...wtf is wrong?

[Gil Bang 25921]

GF's kid's car.  It will idle smoothly in N or Park, but is rough when in Drive or Reverse.  

No check engine light, and no codes stored in computer.  

200,000 miles.    New plugs, new coils.   Runs fine except at idle. 

[Parliament 14247]

Could be running lean because of a bad O2 sensor.  It's a cheap fix.  Next would be intake gasket, MAF sensor and all the plumbing behind it.  If you have air getting in AFTER the MAF, your motor'll run all wonky.

[TwiceHorn 31440]

Sounds like a fuel delivery/mixture problem.  Fuel filter, fuel pump, O2 sensor (controls mixture).  Does it get better or worse when it reaches operating temp?

MAF is another one = mass airflow sensor.

Edited February 3, 2019 by TwiceHorn

[Walte464 450]

Could also be spark plugs the vehicle doesn’t like. Changed plugs on a Jeep, used the higher end ones and it idled hard, changed them again to $2 dollar plugs and it ran like a dream.

[Gil Bang 25921]

1 hour ago, Walte464 said:

Could also be spark plugs the vehicle doesn’t like. Changed plugs on a Jeep, used the higher end ones and it idled hard, changed them again to $2 dollar plugs and it ran like a dream.

Problem started about 3 months after installing bosch plugs.  Installed NGK plugs thinking maybe I had a bad one.  Same problem.   

[Gil Bang 25921]

 

1 hour ago, Parliament said:

Could be running lean because of a bad O2 sensor.  It's a cheap fix.  Next would be intake gasket, MAF sensor and all the plumbing behind it.  If you have air getting in AFTER the MAF, your motor'll run all wonky.

 

1 hour ago, TwiceHorn said:

Sounds like a fuel delivery/mixture problem.  Fuel filter, fuel pump, O2 sensor (controls mixture).  Does it get better or worse when it reaches operating temp?

MAF is another one = mass airflow sensor.

wouldn't either of these conditions trigger the check engine light and throw a code?

[TwiceHorn 31440]

17 minutes ago, Gil Bang said:

 

 

wouldn't either of these conditions trigger the check engine light and throw a code?

You'd think yes, but stranger things have happened.

[Walte464 450]

When i had a bad 02 sensor, no codes were thrown. It’s a cheap part, doesn’t hurt to start there.

[Gil Bang 25921]

there are two, and they are $160 bucks each.  I don't want to burn $320 on something that "may" work. 

[Jkwellborn 6692]

Vacuum leak maybe.

[TwiceHorn 31440]

6 minutes ago, Gil Bang said:

there are two, and they are $160 bucks each.  I don't want to burn $320 on something that "may" work. 

Fucking Toyota parts, man.  Any other vehicle that would be 20 bucks. 

 

Does it get any better or worse when it gets warmed up?

[dingleberryswitzer 2724]

Which Toyota engine is it?

[Gil Bang 25921]

"fucking Toyota"...

Oh boy.  Fucking Toyota indeed. 

So here's the longer version of the story. My GF is a great lady.  She's tough as nails, but her ex-husband doesn't know shit, and her kids don't know shit.   Ex was the heir to a condom company (which shall remained unnamed, but think J.T. Daniels and you're getting warm), and was disowned by his father after the father remarried a much younger woman.  So, he grew up a wealthy, privileged asshole that never had to do anything, which was OK when he had money,  and he ended up a broke-ass know-nothing asshole, which sucks. 

Anyway, he never taught his boys shit. 

So, GF's son starts having car problems, in the worn-out Toyota that GF gave him when we bought the new car.  One of his buddies tells him to check the spark plugs.  So, he gets out the Craftsman socket set that I gave him for Xmas, gets the socket that says "spark plug socket" in the little plastic box,  and goes to work...after removing the coil.

Here's the trouble;   The socket was a 5/8, as one would expect.  Meanwhile, fucking Toyota plugs are 9/16.   So, tl/dr, he gets this socket wedged down the fucking spark plug tube and cannot get it out.  I end up having it towed here to the house, and after several hours, I finally get the fucker out, replace the now destroyed plug with a new one, and try to fix the issue, and here we are. 

How did I get it out?  I drove a lag screw into the socket with my impact driver and was then able to pry the fucker out, only after using generous quantities of WD40. 

[Gil Bang 25921]

3 minutes ago, dingleberryswitzer said:

Which Toyota engine is it?

1.8

[TwiceHorn 31440]

2 minutes ago, Gil Bang said:

"fucking Toyota"...

Oh boy.  Fucking Toyota indeed. 

So here's the longer version of the story. My GF is a great lady.  She's tough as nails, but her ex-husband doesn't know shit, and her kids don't know shit.   Ex was the heir to a condom company (which shall remained unnamed, but think J.T. Daniels and you're getting warm), and was disowned by his father after the father remarried a much younger woman.  So, he grew up a wealthy, privileged asshole that never had to do anything, which was OK when he had money,  and he ended up a broke-ass know-nothing asshole, which sucks. 

Anyway, he never taught his boys shit. 

So, GF's son starts having car problems, in the worn-out Toyota that GF gave him when we bought the new car.  One of his buddies tells him to check the spark plugs.  So, he gets out the Craftsman socket set that I gave him for Xmas, gets the socket that says "spark plug socket" in the little plastic box,  and goes to work...after removing the coil.

Here's the trouble;   The socket was a 5/8, as one would expect.  Meanwhile, fucking Toyota plugs are 9/16.   So, tl/dr, he gets this socket wedged down the fucking spark plug tube and cannot get it out.  I end up having it towed here to the house, and after several hours, I finally get the fucker out, replace the now destroyed plug with a new one, and try to fix the issue, and here we are. 

How did I get it out?  I drove a lag screw into the socket with my impact driver and was then able to pry the fucker out, only after using generous quantities of WD40. 

Any chance you dinged the threads and created a compression leak?

Rough running can be a bitch to diagnose.  At least it doesn't do it in normal driving.

[Gil Bang 25921]

No chance.  The plug was firmly seated when I got the socket out.   The porcelain shit was cracked all to hell, and I carefully removed it with tweezers, compressed air, a shop vac, and everything else I could think of until I was convinced that there was no debris to  fall into the cylinder once I removed the damaged plug. 

And compression leak doesn't make sense, because it only idles rough in D or R.  In P or N it idles smoothly. 

Makes me wonder if the torque convertor, or some electronic item controlling it, is malfunctioning.  Assuming it has a torque convertor.  I'm WAAAAAY behind  on cars.  last two I seriously wrenched on were an old Mustang, and a '56 F100.   New shit baffles me. I'm good with my hands and  can handle mechanical items, like swapping a starter or alternator or similar, but diagnosing electronics isn't in my wheelhouse. 

I just had a transmission failure on the Mercedes (warranty item, thank heavens), and here's how clueless I am:  I thought we had a car with an Automatic Transmission.  I learned that we actually have a car with a manual, but that the clutch and shifting is done by a computer.  Fuck me.  

But make no mistake, I'm not sentimental for old cars.  Working on them was easier, but newer cars are so, so much better in every way imaginable.  I have no desire to own a "classic" of any kind these days. 

Edited February 4, 2019 by Gil Bang

[Chilly Water 415]

Could be fuel issue: pump shitting out or clogged/dirty injectors. Possibly a vacuum leak. If no check engine light and no codes, you could hook up a vacuum gauge and check for leaks. Also could hook up an ODB II scanner and look at fuel trims, that can point you in the right direction 

[Gil Bang 25921]

I've got the scanner, but "fuel trims"?  WTF?  

Off to the googles. 

As to the pump, the car consumes more fuel at highway speeds than at idle.  It runs down the freeway just fine.  Wouldn't a fuel pump issue show up at higher speeds?

 

I've got a vacuum gauge.  I will look for a leak tomorrow. 

Edited February 4, 2019 by Gil Bang

[TwiceHorn 31440]

47 minutes ago, Gil Bang said:

I just had a transmission failure on the Mercedes (warranty item, thank heavens), and here's how clueless I am:  I thought we had a car with an Automatic Transmission.  I learned that we actually have a car with a manual, but that the clutch and shifting is done by a computer.  Fuck me. 

Bah.  That's still an automatic.  It just doesn't have the fluid coupling (torque converter) that prior ATs had.  If it doesn't have a manually operated clutch, it's an automatic. 

You are probably right about the fuel pump, but sometimes they do weird shit on the way out.

[Parliament 14247]

 
wouldn't either of these conditions trigger the check engine light and throw a code?

I had the intake gasket go bad on a Chevy pickup. Idled rough; was fine other than that. Never threw a code.

[Jkwellborn 6692]

Is it possible you cracked a plug?

[Gil Bang 25921]

22 minutes ago, Jkwellborn said:

Is it possible you cracked a plug?

removed and inspected them all.   Is a visual inspection adequate?  And wouldn't that throw a code?

[Jkwellborn 6692]

Not necessarily. My brother cracked one when he did a tune up. Took forever to figure it out. It would stutter for no reason, took a couple of days to throw a code.

Heck, I’ve had the electrode end on a spark plug come unscrewed on a fairly new plug and do the same thing. It would stutter and miss at low engine speeds. It was random as heck. Took a couple of months before it did it good enough to show a code.

[Shoxthemonkey 1977]

3 hours ago, Jkwellborn said:

Vacuum leak maybe.

This. My 2004 Merc Grand Marquis  with 200,000 miles had similar symptoms a couple of months ago. It never showed a code. The mechanic found a crack in a vacuum hose and fixed the problem. Less than $50 and it runs fine now.

[El Tri 412]

i bet you it's the MAF, mass airflow sensor. My lexus did the same thing. Take it off, and grab a can of compressed air and make sure the little filaments are clean. if it has 200k miles you may just want to buy a new one. check on ebay should be able to get one for under $50 new

[Sparky 149]

It might have messed up a plug wire when changing out the plug.  If they are older then they will get brittle around the part that connects to the plug..  If not sounds like a fuel issue, probably a injector clogged.

Edited February 4, 2019 by Sparky

[Jkwellborn 6692]

When it gets dark, raise the hood and disconnect the light. Start the engine and see if you see anything shorting.

[deadshank 24652]

18 hours ago, Gil Bang said:

 I don't want to burn $320 on something that "may" work. 

Aren't you married?  Didn't you learn from that?

[Gil Bang 25921]

49 minutes ago, Sparky said:

It might have messed up a plug wire when changing out the plug.  If they are older then they will get brittle around the part that connects to the plug..  If not sounds like a fuel issue, probably a injector clogged.

No plug wires on this car. Coils attach directly to plug

[Gil Bang 25921]

2 hours ago, El Tri said:

i bet you it's the MAF, mass airflow sensor. My lexus did the same thing. Take it off, and grab a can of compressed air and make sure the little filaments are clean. if it has 200k miles you may just want to buy a new one. check on ebay should be able to get one for under $50 new

I pulled the MAF, and it's clean as a whistle.  No buildup or corrosion.  I blasted it with contact cleaner anyway. 

[Gil Bang 25921]

OK, now it's throwing a cyl. 4 misfire code.  Time for a new plug and coil

[NotActuallyALonghorn 4975]

Might just be a weak battery. I had a misfire once and changed the plug and coil only for the problem to persist. Got a new battery and it worked just fine.

[Jkwellborn 6692]

OK, now it's throwing a cyl. 4 misfire code.  Time for a new plug and coil

You can swap it with another to make sure that’s it. I’m more of a fuck it type person. If I’m taking that shit off, I’m putting another one on.

[Gil Bang 25921]

I tried the swap.  It was a 3 misfire, so I swapped coils between 3 and 4.  Now it's a 4 misfire, so time for a new coil.  

[Parliament 14247]

You can swap it with another to make sure that’s it. I’m more of a fuck it type person. If I’m taking that shit off, I’m putting another one on.

Good advice there.

[Longhorn Al 440]

I changed coils on my friend's Corolla.  Aftermarket coils apparently are crap.  They were recently replaced again with Toyota coils, and it seems to have fixed the problem.

[Gil Bang 25921]

So, compression checked out fine.  I went into a well-established, busy local shop.  Told the owner what was going on; he says the problem is almost certainly a bad injector. 

$500 bucks to repair. 

[elfenix 34225]

from youtube that doesn't look like a particularly difficult fix

 

[Jkwellborn 6692]

YouTube lies.

[elfenix 34225]

also true. 

[tbone_ 14113]

Fetzer valve. Dumbasses.

[dcbc 14465]

Late to the party, but any chance that liberal application of WD40, necessary though it may have been, gummed up the works in Cyl 4?

[Gil Bang 25921]

Update:  I took  it to a mechanic.  The Cyl. #4 codes were a red herring.  Low compression in Cyl 3, most likely a burned valve.  Mechanic says with 200.000 on it, it's not worth fixing.  Drive it until it drops, so that's what the GF's son is going to do.