rough idle, throttle unresponsive when cold
- Thread starter stumpie
- Start date
joegr
Dedicated LVC Member
Sorry. I haven't been keeping up. Are you talking about the resonators on the intake (between the filter and the throttle)?
They smooth up the airflow so that the maximum amount of air can get into the engine at full throttle and since smoother air flow is quieter, they reduce noise too.
ha.
Yea youre probably right. I almost expect the issue to come back after a couple startups.
The silencer has no cracks in it. I cleaned and inspected it thoroughly when I did the work outlined in this thread on March 3rd. I didn't know that's what that thing was called!
if you did not follow the new battery procedure in the owners manual and the drive cycle procedure in the shop manual your rough idle and lousy throttle response probably will return due to improper calibration. if you calibrate correctly your problem will disappear <assuming you fixed everything correctly>.
also, if you run 87 octane again your problems will return.
shaking your head up and down in agreement. good for you littlerig
<stop using these> <its my thing> <get your own thing>
M4rk, I'm soon throwing a 70 pound sub box in the trunk so I think I'll hold on to the cap for extra support.
jrand, that drive calibration thing can't be followed in Austin, Tx. I try to follow it as close as possible but it usually ends with me having to decide to either run this red light or break the calibration steps. I go through the calibration over a couple days, making sure to complete as many steps consecutively as possible.
I've come to the conclusion that my problem is not "drive calibration" related. It's not octane related either. Although I have made a vow to only use 93 Techron, I've driven over 500 miles on it the three weeks and still have the rough starts. It might be bad cat(s), PCV (will be testing vacuum this weekend), fuel delivery (will be checking fuel pressure at the lines this weekend), or the throttle body itself.
As a note, when the engine is idling rough, almost stalling, I can smell fuel so I know it's running thick and has to do with fuel:air. New plugs and COPs pretty much rules out improper combustion.
Again, this condition only lasts until I get it in (D) drive and go. (R) Reverse is still a b!tch. Once driving, if I come to an idle within the first 5 minutes of driving or so, the idle will roughen up a bit but not as bad as first start. After the five minutes, its all smooth. Restarts are usually okay unless the car has cooled considerably.
jrand, that drive calibration thing can't be followed in Austin, Tx. I try to follow it as close as possible but it usually ends with me having to decide to either run this red light or break the calibration steps. I go through the calibration over a couple days, making sure to complete as many steps consecutively as possible.
I've come to the conclusion that my problem is not "drive calibration" related. It's not octane related either. Although I have made a vow to only use 93 Techron, I've driven over 500 miles on it the three weeks and still have the rough starts. It might be bad cat(s), PCV (will be testing vacuum this weekend), fuel delivery (will be checking fuel pressure at the lines this weekend), or the throttle body itself.
As a note, when the engine is idling rough, almost stalling, I can smell fuel so I know it's running thick and has to do with fuel:air. New plugs and COPs pretty much rules out improper combustion.
Again, this condition only lasts until I get it in (D) drive and go. (R) Reverse is still a b!tch. Once driving, if I come to an idle within the first 5 minutes of driving or so, the idle will roughen up a bit but not as bad as first start. After the five minutes, its all smooth. Restarts are usually okay unless the car has cooled considerably.
i guarantee you those symptoms can be related to a litany of sensors not being set correctly. been there done that. in fact I am going through it now bc i had to disconnect my battery:
sulfur smell and rough idle, probably even had a misfire, on the first time i fired it up. after i ran the battery procedure and the drive cycle procedure those symptoms are gone.
you need to not only disconnect the battery, you need to hold the + and - cables together for like 2-5 (i dont remember exactly how long) mins to properly clear the KAM. Unless you have another issue, which you very well might, given that you ran it so long with incorrect fuel, improper calibration can and will cause the symptoms described.
that thing you posted is not the right drive cycle for an 05, i dont remember what yr you have, but give me a minute and ill hit you witha link to the thread where the guy posted it
sulfur smell and rough idle, probably even had a misfire, on the first time i fired it up. after i ran the battery procedure and the drive cycle procedure those symptoms are gone.
you need to not only disconnect the battery, you need to hold the + and - cables together for like 2-5 (i dont remember exactly how long) mins to properly clear the KAM. Unless you have another issue, which you very well might, given that you ran it so long with incorrect fuel, improper calibration can and will cause the symptoms described.
that thing you posted is not the right drive cycle for an 05, i dont remember what yr you have, but give me a minute and ill hit you witha link to the thread where the guy posted it
I don't know just where he got "drive calibration" calibration instructions, but I can tell you I have never had to do such a procedure on any of the many, many cars I've owned. You might even be surprised to know that at the factory the cars are driven off the line onto a dyno and then floored for almost a minute! I almost lost it watching that!
this would apply to electronically controlled cars only and even then, the LS only. im sure the service manual is different for other cars...
it is about the equivalent of rebooting your pc...
the moral of the story is, if you install a code checker and you have p0100 (which doesnt throw a check light) after a battery disconnect, your car has not completed calibration. even if p0100 is NOT present you can still technically be within spec and have your car run/shift like sh*t (ie clunky shifts that dont throw a code, misfires that dont throw a code, etc). the process is very adapative the first handful of time you start the car.
sulfur smell, rough idle, crappy shifting, bad fuel economy, and misfires are normal with a p0100 because half the sensors arent set yet.
sulfur smell, rough idle, crappy shifting, bad fuel economy, and misfires are normal with a p0100 because half the sensors arent set yet.
