04 problem
 

Hi.
I need some help in diagnosing a problem with my 04.
It feels like My engine is not giving everything.
At high rpms in gears 1-3, 6 to 8 grand is smooth but has a thoughty sound as if I were dragging a dead cylinder.
In gears 4&5 it breaks up and feels like it's misfiring at 6 to 8 grand. Some times I get a CEL or a misfire code but most of the time I do not,, and only in the top two gears.
Engine is also idling low and rough at just under a grand when the fan is on, even at the low setting.
I have changed wires, plugs and coils but the problem persists.

Anyone been here?

04 problem
 

Could be many issues:
Cat converter
Fuel pump/ delivery
Eccentric shaft position sensor
Maf
Air filter
Ignition incorrectly installed
Air leak

EDIT: when did you change the ignition ?

++ ^^

Start by cleaning things. The steps in the Congrats thread (my signature block) will get you started.

Then, things like miles, how long this has been happening and any recent changes will help.

Did you get the codes for the CEL?
If one is P0420, your cat is bad, if you still have one.
Misfires kill cats, bad cats kill engines.
Replace, or gut it if so.

Happy New Year and Thanks for the feed back.
The problem has been persistent for 6 or so months.. as I said, I started by changing the plugs, wires and coils. None of that helped.
The CEL I get 'sometimes' when this is happening reads as #1 misfire.
There is no bad cat code, at least not yet. Hoping to figure this out before that.
I have also had a small emissions leak cel that I would clear and have been attributing to the gas cap.
I got a new gas cap yesterday and then drove it 40 miles today.
The problem got worse. Now it breaks up in 3rd gear at 6-8 grand as well as 4th and 5th and I get an intermittent, flashing CEL.
When I go to real time data the only thing I can see different is the fuel system #1 which goes from CL to OL- Drive when I let off the gas or when the CEL starts flashing.
And even with all this, it still passes inspection.

If you still have a catalytic converter, it might be a good idea to have it checked out.
Clogged cats can cause misfires, and if you had misfires before you changed the ignition components, there's a good chance it's bad.
Your symptoms are classic of a clogged cat.

You should also clean your ESS and MAF sensor as stated earlier if you haven't.

Is it possible to have a clogged cat and not get a code?

I don't know for sure.
I had one when mine went bad, but I can't say with 100% certainty that it always happens.
It's not hard to take it off and look at it to eliminate that possibility.
Many of us have midpipes for peace of mind because cat failures are so common.

Unusual, but yes.

Have you done any troubleshooting on the parts I recommended in my first post?

Do yo mean the ambiguous 'could be many issues' list? Yes, and thank you.
I double check for a bad cat code. It has a 10 month old O2 sensor (aft) and the wires are still connected properly.
Fuel pump/ delivery would be the same at high RPM's in any gear so I would like more on why you suggested that.
The car is up on a ramp now, ready to clean the ESS
I cleaned the MAF with MAF cleaner.
I have ordered a new air filter but think the same way about that as I do the fuel pump/ delivery suggestion.
Since I had the problem before I replaced the coils, wire and plugs I can speculate that their install was correct. I have not touched any other parts of the ignition system. They are stock and thus precludes their being incorrectly installed, since the problem is only 6 months old.
Air leak? Where and in what system are you referring to? And wouldn't there be a CEL & code for that?

While it's up, drop the cat and shine a light through it to be sure.

:ylsuper:

I cleaned my MAF and replaced my Air Filter. Then I took it out for a test drive and the problem was gone. Thanks to Soldier and every one who offered assistance.:yesnod:

Don't thank me. Thank my ambiguous 'could be many things' post... :rolleyes:

I still had the weird sound like I was dragging a chamber in high gears, at high RPM's but lost all CEL and breaking up for a while. But the problem wasn't solved for long. Last Saturday night, while on the parkway, I began getting a flashing CEL. I plugged in my code reader and came up with 2 codes. First was #1 misfire and the second was something about the CAT being too lean. I erased the codes to see how ling it would take for them to come back. Thus far they haven't. but I did notice, on the way home, while in 6 gear and cruise control I tried to accelerate but nothing happened when I hit the gas. I steeped on it for a few seconds and then let off. After doing so, with my foot off the gas, gradually the speed increased two mph and then fell back to the set limit.
Today I picked up some fuel injector cleaner and will run that in this fill up.
So much for the list and the scatter gun approach. back to the drawing board. :uhh:

Could be many issues:
Cat converter
Fuel pump/ delivery
Eccentric shaft position sensor
Maf
Air filter
Ignition incorrectly installed
Air leak

It's not scatter gun, its one of these things. Eliminate some and the list will be shorter.

The dreaded "lean cat" code?


Something like 'below efficiency threshold'?

Prepare for the 'choked cat engine terminator' code.

didn't see that one on the list. but it doesn't sound good

I checked 2,3,4,5 and 6 that already.
problem only in gears 4,5 & 6 when I bring the rpms up over 5 grand.
If it were a fuel pump issued shouldn't I have it in all gears at high rpms?

Fuel pump issues can be intermittent.

I did not see anywhere that you said you physically inspected the catalytic converter, unless your emoji response was meant to affirm it.
I don't speak emoji, so I don't know what that was for.

That's because I was being a smartass.

When we are trying to help people, and they come back with "something about" the code, it can be exasperating.
You should at least write down, or take a picture of your trouble code.

Why do I even bother giving advice if people aren't prepared to follow? Why does anyone give advice?
Tell you what- you tell me what you think is wrong, and then you go verify it, and then you come back and tell me what the outcome is.
And I respond with an ambiguous answer which you won't follow anyways.

That's pretty much what's happening here...

normally I do try to write down my codes and then look them up before asking people for help. This last time I was pretty sure I would get the code again and I was driving when I read, and then cleared them. I was surprised when they didn't come back.
I made the same trip today with a full tank and injector cleaner and got no codes, no CEL and the sound I have been referring to was even gone. Could it have been that easy or is it just till the next time, one can only guess.
And even though I ask questions when some answer doesn't make sense to me, I do appreciate all the help.

Oh stop!
First off your list was like saying it's gotta be fuel,spark or compression. maybe you might wanna reread my original question you were supposedly answering. But OK, I punch your check list anyway. You can't handle any questioning when things don't make sense to me like you some kinda premadonna and when I find something that seems to have worked and acknowledge your help you can't even accept when I tell you that you were a help and say thank you without getting all passive aggressive. And now you gonna wine and make like your all offended.
So why do you even bother giving advice. (rhetorical)