my wife's car (2000 toyota echo with about 145k) started bucking today when she was almost home...i just turned it on to see what she was talking about and sure enough, when you move it from park (the idle seems a bit rougher than it should, but that might just be my imagination), it starts to buck (or "throb")...not even driving it, it just sits there and it gets pretty rough (the interior lights would even dim in rhythm with the throbbing)

i don't know how to describe it...it's not severe bucking, but it's a definite, rhythmic throbbing when in any gear (it's an automatic)

thoughts?

2/14/2012 9:32:42 PM

Sounds like its in heat

2/14/2012 9:38:38 PM

transmission or drive train would be my guess. can you hear any rubbing or scraping sounds from it on the outside? like can you pinpoint an area where it happens?

2/14/2012 10:06:58 PM

check ATF

2/15/2012 1:39:53 AM

Sounds like a misfire to me - bad coil, wire, or plug. You should have a CEL if that's the case, but put a scanner on it and pull any codes to be sure.

2/15/2012 7:43:49 AM

Quote :

"transmission or drive train would be my guess. can you hear any rubbing or scraping sounds from it on the outside? like can you pinpoint an area where it happens?"

transmission was my guess, too, simply because it only happens when in gear...i didn't hear anything in particular from the outside, but i didn't have a chance to pop the hood...i just verified that it was acting up and told her i'd drive her to work until i could check it out and get/or get it to someone

Quote :

"check ATF"

d'oh, didn't think about that

i've never owned a car with an automatic transmission, so i forget there's fluid for it

Quote :

"Sounds like a misfire to me - bad coil, wire, or plug. You should have a CEL if that's the case, but put a scanner on it and pull any codes to be sure."

no CEL

i'll check the ATF and listen for more specific sounds at lunch and report back

2/15/2012 8:03:52 AM

The reason I mentioned it was because my wife's car had the exact same symptoms and I initially assumed transmission. When not under load (idling) it would run a little rough, but once it was in gear and moving, especially at speed, it would hesitate and lurch pretty badly. The OBD told me that it actually had a misfire on the #5 - I think it cost like 30 bucks for a new coil and about 20 minutes of my time to fix.

If you want to test the transmission theory quickly, put it in neutral, off the brake, and see if it still bogs down or moves. If it sits still, but bogs down or hesitates, it's probably something in the engine.

[Edited on February 15, 2012 at 10:50 AM. Reason : .]

2/15/2012 10:49:28 AM

first...i can't find the ATF dipstick

to be fair, though, i only had a couple of of minutes and didn't look too hard...i just didn't see it immediately (though i found all the other caps just fine)

never mind, a quick google search tells me that it's the red stick that i was wondering about...it had nothing but japanese on it, so i wasn't sure

second...i popped the hood and watched the engine when she put it in gear (foot still on the brake, of course) and it went from a (slightly) rough idle to outright shaking

given the rhythm, i'm wondering if is indeed not transmission related and perhaps something with the engine

third...i still did not see a CEL, though i might turn it on this afternoon and let it run for a while to see if it comes on

given the shaking, would it be a bad idea to drive it 5-6 miles to advance to get them to get a reading? i could always go buy an OBD reader from harbor freight for cheap, though

i'll do ^ when i get home this afternoon

[Edited on February 15, 2012 at 12:19 PM. Reason : found it!]

2/15/2012 12:17:52 PM

transmission mount?

2/15/2012 1:15:56 PM

ATF level and color are fine
still no CEL
park and neutral yield slightly rough idle, in-gear yields significant, rhythmic vibration (engine visibly shakes)

google (and y'all's suggestions) make me think it's a mount and that it's not a huge deal...though my brother has my stands and jack and even if i knew what to look for, i can't get it up there to check

misfire is a close second

[Edited on February 15, 2012 at 5:23 PM. Reason : .]

2/15/2012 5:20:28 PM

how long has it been doing this? you might have a pending code in which the CEL won't come on but the code is still stored. i had a bad coil in my M3 and no CEL.

2/15/2012 5:23:30 PM

^ just started last night...i left the car on for a couple of minutes, but the light didn't come on...would a scanner pick up the code even if the light isn't on?

also, i THINK i smelled something when i was running it...honestly, smelled like my old motorcycle on a cold morning until it warmed up a bit...not sure it's relevant or even related, but thought i'd mention it

2/15/2012 5:49:54 PM

Automatic transmissions are a creation of the devil.

2/15/2012 6:23:23 PM

Check your plugs/wires man!

2/16/2012 7:49:20 AM

^^^^What he and he^ said. If the OBD finds a problem, it stores a "pending" code, but no CEL. Once the reporting sensor passes a certain threshold, it assumes it is in fact a valid problem and stores the code, often along with a copy of all the sensor reading at that point in time (freeze frame). That's why I suggested putting a scan tool on it even though you don't have a CEL - if it's got a pending code, you'll see it there.

Could have a burned out CEL bulb too - remote, but possible. Keeping with my assumption that it's a misfire, if exhaust smells "rich", it may be because one cylinder is blowing gas straight through without burning it.

I'm still sticking with my misfire hypothesis, but at least get a scan tool on it and see if it returns anything pending or stored. If you get a P030x, then that is a misfire and the x is the cylinder at fault. If you happen to be anywhere near Miami Blvd, I keep one in my truck that you can hook up to it real quick.

Another quick way to check for a misfire without a computer is to pull the plug wires or coil packs one at a time. If it stumbles worse and/or cuts out, put it back and try the next one. Once you pull one and nothing changes, that's your culprit.

^^And this x a million. I will never buy another automatic if I can do anything about it.

2/16/2012 7:52:39 AM

FenderFreek was right...bad ignition coil

dan came by last night with the scanner and it was a misfire on cylinder 3 (still no CEL, but as noted by others, i guess it can take some time for it to show up)...spark plugs were awful, so got 4 new ones and a replacement coil ($100! ) this morning

the coil didn't work, but it actually looked used...returned and got another one and the car's running fine (the new, non-copper plugs probably helped, too)

thanks for all the suggestions, and thanks to dan for coming out here to show me how easy it is to (identify and) replace a coil

Quote :

"Automatic transmissions are a creation of the devil."

this has always been my understanding...i've never owned one and really don't want to, though i really want a mazda3 or focus hatchback that have those new super-mpg dual-clutch transmissions from ford and mazda...i suppose that's a slightly different beast than your run-of-the-mill auto

[Edited on February 16, 2012 at 11:11 AM. Reason : .]

2/16/2012 11:09:30 AM

An interesting issue that I feel compelled to expound upon:

This is the SECOND time I've seen a customer get a used or obviously defective coil when they go to get one. It's obvious to the trained eye that a past customer bought one and then returned the original, all cleaned up, for a full refund. And most customers don't know any different (and why should they? they aren't parts pros), just that the new one doesn't work. They don't know that the new one from Borg Warner or whoever isn't going to have a Denso or TEC logo on it. Half the parts people don't either (and this is inexcusable in my opinion, but most stores don't pay enough to lure in real parts pros).

2/16/2012 2:17:44 PM

Quote :

"e those new super-mpg dual-clutch transmissions from ford and mazda...i suppose that's a slightly different beast than your run-of-the-mill auto"

That is not an automatic. That is an automated manual.

[Edited on February 16, 2012 at 7:11 PM. Reason : Valvebodies and torque converters are what I specifically hate]

2/16/2012 7:10:23 PM

^^it is inexcusable but you're right it does happen all the time. it happens so much that i've grown accustomed to pulling the part out of the box every time i purchase something at a parts house.

2/16/2012 9:15:17 PM

Quote :

"(and this is inexcusable in my opinion, but most stores don't pay enough to lure in real parts pros)."

When I worked at Advance in college, they didn't pay enough to lure in parts amateurs, haha. Pretty much if you showed up consistently and on-time to work, and didn't cause any problems, you could have and keep a job there.

2/16/2012 9:17:44 PM

So you replaced the plugs and it kept misfiring then?

2/16/2012 9:35:43 PM

^ replaced all the plugs (they desperately needed it) and it kept misfiring...i then replaced the coil that was being reported as bad and it kept misfiring...i swapped out the (obviously) used coil for a new one, replaced it, and it fixed the problem

2/17/2012 6:49:43 AM

Quote :

"the new, non-copper plugs probably helped, too"

Copper plugs are actually great spark plugs. They just wear out faster than most other types.

Quote :

"though i really want a mazda3 or focus hatchback that have those new super-mpg dual-clutch transmissions from ford and mazda...i suppose that's a slightly different beast than your run-of-the-mill auto"

I'd stay away from those for a bit. I've heard they're pretty rough shifting and a lot of people aren't very happy with them. I'm sure you'd still manage 40+ mpg on the highway with the traditional 6 speed manual transmission.

2/17/2012 9:38:46 AM

Quote :

"Copper plugs are actually great spark plugs. They just wear out faster than most other types."

oh, i didn't mean to say they weren't great plugs...but i knew they wore out faster than iridium plugs and if the iridium plugs cost twice as much but last even as little as twice as long, it still saves me time...i'm lazy

Quote :

"I'd stay away from those for a bit. I've heard they're pretty rough shifting and a lot of people aren't very happy with them. I'm sure you'd still manage 40+ mpg on the highway with the traditional 6 speed manual transmission."

i've heard the same and i'm hoping our current cars (my saturn at about 170k and her toyota at about 145k) will last long enough that they'll have "fixed" them before we're really in the market

besides, i manage 40+ mpg (around 41-42mpg with my regular driving habits) on my 5sp saturn...her 4sp auto gets upper 30s

2/17/2012 10:11:19 AM