Pulsing vibration when idling

[agginline86]

I've had the same issue
Especially after I accelerate and then come to a stop, RPM dip
From a stop shifting into first, occasionally I get a little shaking
When going downhill in neutral (slow speeds, driving out of parking garage),
the car has stalled once, but usually RPMs just dip down to nearly stalling

A month or so ago I took it in and my motor mounts were bad
had to replace them (~$700)
It's been about a month and it's starting to come back
I can hear a slight rattle when driving over bumps/dips
Can also hear it if you listen closely when the car starts (not engine knock)
may be the motor mounts again?
I'm gonna have my mechanic check it out this weekend
I might clean out the IAVC, TB, etc a bit before taking it in

Recently had the timing belt replaced
Up to date on all maintenance
I've got a bad upstream O2 sensor (throws code) and waiting until smog check to replace it, but that shouldn't be the issue

01 honda accord EX coupe
F23A4 (4 cyl, 2.3 L)
5 sp standard
103k
aftermarket I/H/E

 

[619rcr]

I've had the same issue
Especially after I accelerate and then come to a stop, RPM dip
From a stop shifting into first, occasionally I get a little shaking
When going downhill in neutral (slow speeds, driving out of parking garage),
the car has stalled once, but usually RPMs just dip down to nearly stalling

A month or so ago I took it in and my motor mounts were bad
had to replace them (~$700)
It's been about a month and it's starting to come back
I can hear a slight rattle when driving over bumps/dips
Can also hear it if you listen closely when the car starts (not engine knock)
may be the motor mounts again?
I'm gonna have my mechanic check it out this weekend
I might clean out the IAVC, TB, etc a bit before taking it in

Recently had the timing belt replaced
Up to date on all maintenance
I've got a bad upstream O2 sensor (throws code) and waiting until smog check to replace it, but that shouldn't be the issue

01 honda accord EX coupe
F23A4 (4 cyl, 2.3 L)
5 sp standard
103k
aftermarket I/H/E

Why wouldn't you replace a bad upstream o2? It is what the computer uses to fine tune the fuel and directly affects driveability. Downstream just tells if the cat is working and won't affect anything. But whatever, its your car.

 

[619rcr]

Codes are p0500 and p1167

P0500 is vss fault. p1167 is primary 02 htr malfunction. These should not affect the idle. The vss may affect Vtec engagement & speedometer. o2 htr would cause the o2 to take longer to start responding at cold start up. I could maybe see this being a problem at cold start idle... maybe. but not likely, since the ecu uses a base map at cold start & once the o2 heats up and the eng goes into closed circuit fuel, the o2 is used to alter the fuel trim.

I would still think about doing a tune up first. Then either clean your intake professionally or yourself. Dirty throttle bodies, can cause a rough idle & engine stalling, which in turn would result in a vibration. The Idle air control passages could be dirty too. Disassembling the intake & cleaning everything by hand and replacing the gaskets is the best way. But a professional tb cleaning may help if they actually do it right.

 

[x5carl3tMurd3rx]

are you v6 or 4cyl?

 

[619rcr]

are you v6 or 4cyl?

He is 4cyl MT

 

[JniG]

P0500 is vss fault. p1167 is primary 02 htr malfunction. These should not affect the idle. The vss may affect Vtec engagement & speedometer. o2 htr would cause the o2 to take longer to start responding at cold start up. I could maybe see this being a problem at cold start idle... maybe. but not likely, since the ecu uses a base map at cold start & once the o2 heats up and the eng goes into closed circuit fuel, the o2 is used to alter the fuel trim.

I would still think about doing a tune up first. Then either clean your intake professionally or yourself. Dirty throttle bodies, can cause a rough idle & engine stalling, which in turn would result in a vibration. The Idle air control passages could be dirty too. Disassembling the intake & cleaning everything by hand and replacing the gaskets is the best way. But a professional tb cleaning may help if they actually do it right.

After doing a bunch of research, Ive decided to order a new o2 sensor and replace it. According to what I've read on google, a bad o2 sensor on a ULEV engine is likely to cause a few issues, including rough engine idle and poor fuel economy (both of which I am experiencing). It sucks that the sensor for ULEV vehicles are so much more expensive than non ULEV sensors, but hopefully this fixes my problem. I'll let you guys know how it goes.

And also, I think I'll take your advice and do the tune up and throttle body clean too. Seems like a good thing to do for my car. Thanks everybody for the useful information. Reps for everybody! And and report back once I install the new sensor.

 

[agginline86]

Why wouldn't you replace a bad upstream o2? It is what the computer uses to fine tune the fuel and directly affects driveability. Downstream just tells if the cat is working and won't affect anything. But whatever, its your car.

I do plan on it, it just isn't "necessary" yet
plus the one I have currently may still work, it just isn't pinned out properly
I made a thread months back to no avail.,
I think I wired everything back up properly but I still am unsure if the sensor itself is bad.

When I was putting my headers I accidentally pulled the wires out of the harness, no indication of what wire connects to what terminal, two wires the same color, etc
So hypothetically i think it still works
Googled and searched everything on every forum I could find

New members just get **** on here... so I just said **** it after I posted

 

[JniG]

I do plan on it, it just isn't "necessary" yet
plus the one I have currently may still work, it just isn't pinned out properly
I made a thread months back to no avail.

When I was putting my headers I accidentally pulled the wires out of the harness, no indication of what wire connects to what terminal, two wires the same color, etc
So hypothetically i think it still works
Googled and searched everything on every forum I could find

New members just get **** on here... so I just said **** it after I posted

I've done a bit of reading and it's actually quite likely that a bad upstream o2 sensor will cause a rough idle. It's also called an air/fuel ratio sensor (specifically for the sensor thats attached to the center of your exhaust manifold) which (i think) detects oxygen levels in the air and determines how much fuel to burn. A bad sensor can make your engine run too rich or too lean, negatively affecting your fuel economy. I've read that a common symptom for a bad sensor is rough idle. A month ago, your o2 sensor was still good and your rattling was caused by the engine mounts. They shouldn't give out in just a month so your vibration problem is very likely to be the same as mine, since your symptoms sound very similar to mine and you also have a CEL for a bad upstream o2 sensor. We'll see once I get mine replaced.

 

[agginline86]

I've done a bit of reading and it's actually quite likely that a bad upstream o2 sensor will cause a rough idle. It's also called an air/fuel ratio sensor (specifically for the sensor thats attached to the center of your exhaust manifold) which (i think) detects oxygen levels in the air and determines how much fuel to burn. A bad sensor can make your engine run too rich or too lean, negatively affecting your fuel economy. I've read that a common symptom for a bad sensor is rough idle. A month ago, your o2 sensor was still good and your rattling was caused by the engine mounts. They shouldn't give out in just a month so your vibration problem is very likely to be the same as mine, since your symptoms sound very similar to mine and you also have a CEL for a bad upstream o2 sensor. We'll see once I get mine replaced.

Yeah keep us updated
Thanks for taking the time to research

I'm aware that the o2 sensor is likely the cause of the rough idle,
however my issue is much less the rough idling (idles around 750 rpm unless I'm coasting downhill) than the noise/rattling. I have to check into it a bit more. I think you're alluding to why I haven't bought a new one. If the sensor went bad due to the engine vibrating, obviously have to fix the vibration first.

If you new o2 sensor fixes it, I guess I'll have to move getting a new sensor higher up on my priorities hah

 

[metrick1235]

another good place to check too is make sure a Vacuum hose hasnt disconnected.. I Pulled the top end off my motor a while back and forgot to connect one of them back and it did the same kid of symptoms... Just a suggestion