Finding a Good Diagnostician

Shel_B said:
There is a subtle roughness at low engine speeds that seems to diminish at higher revs, over about 2200rpm. However, I think the roughness may be masked by the engine rpm. I don't have an OBD scanner, however, I had a trusted shop go through the car, looking for codes and examining systems for problems. No codes turned up, all of the systems they checked were fine. nonetheless, the roughness persists.

I'm planning to put in a new set of plugs, maybe that would help, but I'm not doing the plug change just for this roughness ... it's about time to change 'em regardless. However, I do not want to just throw parts at the problem. I'd like to find someone who can take the time to drive the car, who has some sensitivity to the way an engine should run and sound, and who has the experience, the tools, and the temperament to delve into the issue.
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I think a scanner is a standard tool everyone should have. A couple that come to mind is the Autel AP200, does all manufacturer specific error codes in addition to standard OBD error codes. Thinkcar Pro is also good, used to be more than Autel but now cheaper. At the very least, you should get one that does standard OBDII error codes.



 
I think it is also important to recognize that not all driveability issues require a scope to diagnose, and a scope may not always be the most efficient method of diagnosing an issue.

A scope is just another tool in the Arsenal. It is used when and where appropriate. Just because it is available doesn’t mean it is the most efficient approach for every situation.
 
From sitting on my couch, I'd recommend you try 1-2 bottles of Chevron Techron fuel injector cleaner, new spark plugs, and inspect the tensioner on the serpentine belt...if this is starting to fail the off idle roughness might be a symptom if the noise is not so loud yet.
 
Besides the mention basic items like plugs, fuel injector cleaner, You do need a basic scanner that provides live data. This data can give you basic info like the engine temperature, air mass readings, O2 function: These plus other para meters is what the computer uses to adjust the fuel and timing of the engine.

Do a basic inspection and check all hoses, a leak will drive the computer crazy.
 
Also, a "subtle roughness" is going to be difficult to convey unless you have a side-by-side example of the same vehicle. Unless of course, the issue is blatantly obvious.
 
If your spark plugs and wires are due to be replaced, you're not throwing parts at the problem (per se) to continue to do the maintenance it needs anyway. I see no reason to wait on that and it might just solve the problem too.

How long has it been happening? Could it be as simple as a bad tank of gas?
 
Indeed, which is why I try to wait until the problem gets worse and others can hear/feel/see the problem too.

Waiting until the offending item falls off works pretty good too...
 
Dave9 said:
If your spark plugs and wires are due to be replaced, you're not throwing parts at the problem (per se) to continue to do the maintenance it needs anyway. I see no reason to wait on that and it might just solve the problem too.

I seem to recall saying just that ... Great Minds ...
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Dave9 said:
How long has it been happening? Could it be as simple as a bad tank of gas?
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No, it's not a bad tank of gas. It's been going on for close to a year. During that time there have been two tanks with Redline SI-1 fuel system cleaner, a check of all belts and pulleys, a scan for any codes, tire rotation, and road force balance, and I cleaned out my coin tray. All of this was part of regular maintenance and preparation for a long road trip, not specifically for the problem.
 
Dinoburner said:
To do the basics before going to a shop or not to and let them have it untouched. Me, i`d do it along with written details.
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rough transition is usually a delightfully tiny vacuum hose or EGR leak. Which a pro will track inside 45 minutes.
The rest of us it'll be a fruitless Saturday morning. Pizza, beer. .... Afternoon..... more beers. Muttering.
Then: 'why am I watching 'Ask This Old House' videos?, then some fruitless YT drivability video searches.
Then off to the diagnostics people on Monday. : )
 
Shel_B said:
I seem to recall saying just that ... Great Minds ...
Click to expand...
BUT.. did you DO it?

A shop should not just try to pull codes, if there are no codes then next step is a scanner with realtime data while running. I suppose that's the next "step" in mandatory equipment that any shop necessarily has so I wonder that you aren't mentioning anything further diagnostic than code pulling... could just be poor communication from the shop.
 
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Shel_B said:
There is a subtle roughness at low engine speeds that seems to diminish at higher revs, over about 2200rpm. However, I think the roughness may be masked by the engine rpm. I don't have an OBD scanner, however, I had a trusted shop go through the car, looking for codes and examining systems for problems. No codes turned up, all of the systems they checked were fine. nonetheless, the roughness persists.

I'm planning to put in a new set of plugs, maybe that would help, but I'm not doing the plug change just for this roughness ... it's about time to change 'em regardless. However, I do not want to just throw parts at the problem. I'd like to find someone who can take the time to drive the car, who has some sensitivity to the way an engine should run and sound, and who has the experience, the tools, and the temperament to delve into the issue.
Click to expand...
If the car in question is the 2011 Camry 4cyl - I had one in with rough idle (smooth above idle) and it was a bad motor mount.....check there 1st
 
Shel_B said:
There is a subtle roughness at low engine speeds that seems to diminish at higher revs, over about 2200rpm. However, I think the roughness may be masked by the engine rpm. I don't have an OBD scanner, however, I had a trusted shop go through the car, looking for codes and examining systems for problems. No codes turned up, all of the systems they checked were fine. nonetheless, the roughness persists.

I'm planning to put in a new set of plugs, maybe that would help, but I'm not doing the plug change just for this roughness ... it's about time to change 'em regardless. However, I do not want to just throw parts at the problem. I'd like to find someone who can take the time to drive the car, who has some sensitivity to the way an engine should run and sound, and who has the experience, the tools, and the temperament to delve into the issue.
Click to expand...
Please send me your money cuz it sounds like you are about to throw it away over nothing
 
Johnmpb said:
Please send me your money cuz it sounds like you are about to throw it away over nothing
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Tell me, please, what you know about the car and the situation that causes you to feel that way? I'm also curious about the expertise that allows you to make such a pronouncement from a couple of internet posts. What have I, or anyone for that matter, said that affords you such insight.
 
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GMBoy said:
If the car in question is the 2011 Camry 4cyl - I had one in with rough idle (smooth above idle) and it was a bad motor mount.....check there 1st
Click to expand...
It's interesting that you mention motor mounts. I too had some thoughts along that line and actually made a few inquiries about the possibility. Didn't get any meaningful response. Thanks for reminding me.
 
Dave9 said:
BUT.. did you DO it?

A shop should not just try to pull codes, if there are no codes then next step is a scanner with realtime data while running. I suppose that's the next "step" in mandatory equipment that any shop necessarily has so I wonder that you aren't mentioning anything further diagnostic than code pulling... could just be poor communication from the shop.
Click to expand...
Ordered the plugs a couple of days ago, will put 'em in when I do the next oil change, maybe before depending on the timing.

We just left it at codes and an examination of some aspects of the engine, didn't want to go full diagnostic at that time.
 
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