Surging Problems?

[Bryali]

I've been having an issue with my 05 SXT that has gotten on my nerves. I only have about 10,000 miles left on the warranty and I still can't find a dealership that can help me. Here's the problem:

Every so often, when I first start the car and drive a mile or two, the car will start hesitating. It starts surging and sputtering and the throttle response sucks. If I power through it, it'll eventually clear itself out, but it's still a problem. When I slow to a stop, the car jerks and sputters almost like a manual left in gear without pushing in the clutch. Then when I try to pull away from the stop, it'll spit and sputter again, till I power through it. The tach will bounch with the erratic RPM's, then when the problem has passed, the tach goes back to normal. I've tried finding a pattern (speeds, road conditions, weather conditions, time of day, etc) and the only thing I've found is it mostly happens after the car has sat a while (overnight, while at work, even in shopping). When all this is going on, the "engine" light flashes for a few seconds, then goes away.

I've taken it to a dealership and been told, "It's not doing it now so we can't tell you what's wrong. That'll be $65 for the labor of hooking it up to the diagnostic computer" After telling them where to look for that $65, i leave the dealership pissed off and nothing has been fixed. I life in NY and just had my car tested a week ago and of course, no trouble codes were found. I've gone to Auto Zone, no codes found. I've used a MacTools scanner, no codes. Every time it's started messing up, I've run to the dealership to get it looked at and it quits on the way there.

Anyone else run into this or have any ideas what it may be? I'd appreciate any help.

Bryan

[Magnum P.I]

maybe if you can leave it at the dealership overnight tell them don't touch it untill you get there the next morning and start the car with a technician watchin and then take him for a ride in it. As you said it happens when the car sits for a while. what happens when the car has been running and reach full operating temp..Might be bad injectors. Don't take my word for it though. Better yet lets call the chykn. Hey Funcky Chickn come on out with your expert knowledge.....

[Bryali]

I can't leave it overnight at the dealership because it's our family's only car. Also, it doesn't happen EVERY time it sits. Injector COULD be a problem because every time this happens, my gas mileage takes a hit. In a major way. Based on my simple math of my 25 mile commute each way every day and how far the needle moves, I've gotten as bad as 7-9mpg. Not 7-9 less than normal. 7-9mpg total! Oh, and my drive to work is on a state highway where I set the cruise on 60 till the last 2 miles. Recently I drove over 375 miles, almost all highway, and was getting around 28. Mapquest it. Gouverneur NY to Milton NH and I had around a third to a quarter tank when I got there.

Anyway, maybe the gas mileage is a part of it. Thanks Magnum P.I. Any thoughts Chickn?

[stitchmonkey]

sounds like fuel system issues to me? maybe dirt in your fuel tank?

[RunningBull]

when was a last cleaning of the throttle body
or fuel system.put some seafoam in the tank
auto marine will be on the can.

[fnkychkn]

possible slow response from O2 sensors.

possible saturated vapour canister causing the engine to run rich when purge solenoid activated.

possible candidate for TSB 09-010-06.

possible EGR issue.

your dealer can install a data recorder to capture an event. it should show what is happening at the time of the hesitation/sputtering.

[Bryali]

That TSB really has me interested cause it talks about being under 3500 RPM and that seems to be where it happens. If i can break it loose above that 3500 RPM the problem seems to go away, which from what i read, it forces the exhaust valves to open, regardless of the carbon. Thanks chkn. I'll take these options to the dealership and see what they say.

[Rob A]

Not same vehicle but same issue with the wifes stealth i through the kitchen sink at it, but nothing helped. Got the itch to check the back plugs (after pulling off the intake what a pain to just check plugs.) But would you know had a plug fowled with a bucnh of crap after changing all plugs with iridium plugs problem went away. Had all the same issues you discribed. RPM's below 3500 car just studdard and hesitated but then ran better. You can check coil packs and plugs yourself yyou need voltage meter to check packs though.

[blknblu]

My 79' Camaro used to do that. Like 'Rob A' said it turned out to be fouled plugs. I used to use sandpaper to sand the crap off, clean with a good cleaner, regap, and reinstall. Of course getting to the plugs on an old 350 engine is a lot easier than getting to yours. Good luck.

[Homer426]

I had the same problem in my Hemi. I was able to get some codes off of it.
System to Rich and Slow responce from O2 sensor.
And then to top it all off after all that my radiator went out.

Hate to tell you but after they replaced it I have not had a problem.

[uwsacf]

I would have it MotorVac'd myself...

That will solve or identify any fuel issues and get you ready for emissions testing by cleaning your plugs - egr - even the cats...

big thread I started here...... read a little of it - then go to one of the last pages where we have been keeping a list of shops around the country...

http://www.impalassforum.com/vBullet...light=MotorVac

[Creek Rat]

I have an 05 SXT and it used to do EXACTLY the same thing when it's sat outside on a wet night. The dealer wanted to do the valve spring change and at the time I thought it was baloney on a car with 15,000 miles. Now that I've read more about the carbon problem I wish I have gone along with their recommendation, right or wrong, just to have that fix done.

As for the surging problem I stopped leaving my car outside when rain was in the forecast and the worst of the symptoms never resurfaced.

[bookeem]

this problem is annoying as hell..