Cadillac CTS First Generation Forum - 2003 - 2007 Discussion, 06 CTS 3.6L Rough Idle and Accelaration in Cadillac CTS Coupe, Sport Sedan and Sport Wagon Forums; 06 3.6L CTS
I just bought this car two Months ago and it had started driving strange a couple a ...
I just bought this car two Months ago and it had started driving strange a couple a weeks after buying it. It had 85k miles on it when I bought it(89k miles now with an oil change at 88k miles). The first problems I started having with it was when I was driving it felt like the car was jerking kind of like i was constantly pressing the gas pedal over and over. It did it more noticeably going up hills or when the car was in a strain. You can even watch the rpm guage and it will will fluctuate 200-300 RPMS. When I got my first oil changed my Fuel Filter, checked the Air Filter and cleaned the Throttle Body. That did nothing.
Last week I had my mechanic change out the spark plugs, because it had gotten worse and finally started showing codes, with the check engine light coming on finally. When the first check engine light came on I was driving up a big hill and the car hesitated and started jerking. When I had the car hooked up to a reader it was saying I had a misfire on my #2 cylinder. After my mechanic changed my spark plugs he told me that he didn't replace the intake seal, because it would take 2 weeks to get one on back-order.
So, now after this my car has a really rough Idle. The whole car vibrates every couple of seconds when I'm stopped. It's also still hesitating and having the same issues as before when accelerating. My mechanic asked me to drive it until the check engine light comes on again so that we will know if the #2 Cylinder is still misfiring. He said if it does we can replace the coil on that #2 Cylinder and hopefully fix the issue with the acceleration. Since the car started Idling really bad I don't personally think the coil is to blame on that and it will need a new seal for the intake to fix that problem. Also, after getting my oil changed the first time we noticed that my Rear Seal is leaking slightly. I don't think this could be causing this issue, but thought i would share.
Any suggestions on what else can cause this issue or if I'll need to replace the coil on the #2 Cylinder and the intake seal to hopefully fix this?
*EDIT* Would also like to add that when my mechanic removed the intake he said that it had the metal seal and not that rubber one, and unless I'm mistaken It shouldn't need to be replaced if you remove the intake.
When I read the title I was going to ask if the throttle body or filter had been cleaned recently. I've had two cars with rough idles that were fixed by cleaning the filter and the TB. The only time my car hiccuped badly on accel was when I over oiled an aftermarket intake and again when said intake sucked up a deep puddle. I'm almost certain that the rear diff wouldn't cause jerking and would start whining before it got low enough to cause any real symptoms.
It's odd that only #2 would misfire, which is probably what's pointing him to spark issues. When I botched my air filter I was misfiring on 2 and 4 if I remember properly(inline 4). Were the plugs fouled up badly when he pulled them? Also have you been able to hear any squealing or sucking sounds around the intake? I haven't pulled mine yet, so I can't speak for the seal, but I haven't seen a metal seal on an intake before. He's probably correct, but it couldn't hurt to try. I've seen weirder things already.
Hopefully it all gets sorted out on the cheap. I'm about to clean the TB and Seafoam mine, as it doesn't sputter or choke yet, but it does hesitate a bit on acceleration.
my previous car before i bought my cts was a 2001 buick regal with 3800 supercharged. I had ssame problem with that cylinder misfires, rough idle. I changed plugs, wires, all that stuff. Turns out it was the injector orings. The injectors went right into the top of the heads and orings kept it sealed well they leaked creating a vacuum problem. I changed orings and all was well again. U may have somkind of vacuum leak maybe in the intake plenum gasket or some vacuum line. hope that helped some.
I have the same problem with my 05 3.6l CTS. Im not sure exactly what the problem is. Nothing has been touched to fix this yet. Im guessing a few issues. First, mine will shudder or shake while at idle every so often. Thats probably a misfire every so often (havent had it looked at). Poor gas mileage 18 or so total. Last is a HUGE acceleration issue. When I step on the loud pedal too hard, it jerks back and forth violently and wont go. If I lift off and gently accelerate, its ok.
I have the check engine light on, and there was a purge valve code in it. I have that on order. Im going to change the air and fuel filter then take it to have it checked for misfires. Oh yeah, there is also a rattle in the valve train constantly. Im guessing loose rocker or something like that... too many issues.
With misfires I almost guarantee its the Coil Packs. Especially if you already replaced the spark plugs. Ive had that problem a few times with diff cylinders. Replaced coil packs and all is well again.
Automobile(s): The Mighty Kael, 2004 Black CTS, Every Option
Re: 06 CTS 3.6L Rough Idle and Accelaration
Okay I would say spark plugs first, you changed those.
The gasket on the intake falls apart when you pull the intake off. you HAVE to replace it and scrap off the old one with a razor (be sure to stuff towels in the intake ports so prevent garbage from falling in) You probably have a vacuum leak from the old gasket. The o rings around the injectors would be a cheap check, just spray some water with soap in it, look for bubbles.
Coil packs might be next.
My car would idle in gear pretty rough one day, thought it was weird but it went away, later that day I started the car and it idled even rougher, then I smelled the plastic burning. The coil pack then failed and melted itself to the engine. so that sucked.
I am kinda having same issue. Ck engine light on. Said o2 sensor bank 2. So in waiting to get that fixed . Now only under acceleration sputtered and light flashes. Took back to ck and said misfire in 2. And in 6 . Would o2 sensor cause this??