hey guys, can anyone help me with this problem that i'm having?......some times when i drive my 8 it seems to lose power when i step on the gas. and b4 its cut off its start to shack very hard and off it goes....any info will help me to fix this prob.

 

Year, mileage, mt or at.
When did yu change coils, plugs wires

 

if it was the cat the CEL should come on, unless the cracked part was after the 2nd O2 sensor.

 

I just had this, it was my plugs. Not that it can't be other things but check your plugs.

 

Yup plugs are clogged cat. Start with your plugs and coils then work your way down. GL!

 

coils/plugs...

 

Here we go again!

 

year-05 mil-20k n change AT. I had my plugs changed b4 but not my coil..wat does CAT means?

 

Catalytic converter.
It's the middle piece of the exhaust system that makes you pass the Smog Test.

 

Given your new input.
In my opinion only.

I'd first make sure all plug wires are good and tight at both ends.
Then I think I'd go after all the coils.
If still no good, then it's time to look maybe at the MAF and then the CAT.

New term........MAF = "Mass Air Flow" it's a sensor in the air intake accordion tube.

 

ok guys, but i was wondering. can it be a bad fuel injector? casue it happens after i drive for a short period n come to a complet stop at a light. just wondering

 

ok guys, but i was wondering. can it be a bad fuel injector? casue it happens after i drive for a short period n come to a complet stop at a light. just wondering

 

is there something pointing you to an injector, recent work done etc?

 

+1.
What everyone is telling you above is a good starting point because we've seen similar symptoms that resulted in a clogged cat or bad coils/wires/plugs.
Rule out the common issues first and then we can move on from there if needed.

 

I changed out my '05 coils at ~20k and would also lean to them as the culprit. Good way to eliminate a variable as well. Easy to change your coils yourself, see the DIY by dozer.

 

ok..How would I know if it is my coils that is bad? would it look burnt or what? I know im asking mad questions, but im new to this and i love my 8 so i want to be sure im doing the right thing.

 

Nope. Actually, if the coils look burnt, your engine probably wouldn't run

There is no other indication than one or more of the following:
- Unstable idle
- Loss of power in low RPM ranges
- Loss of power in high RPM ranges
- Mis-fires
- over 20,000 miles since your last coil change (some last to 35-40k, but even that is uncommon)

And of course this is always present:
- Back to running perfectly when you replace them

 

"A search a day keeps the flamers away", but here you go.

 

would bad coils cause the car to vibrate????

 

Yes it is possible.

 

Check your spark plugs. I had this happen to two friends of mine.