shaking engine

[Ricky Soto]

My 07 ST is idling rough. I changed all ignition coils and spark plugs, fuel filter and now i'm out of ideas. It got better, but not like it should for a V8. The roughness is pretty steady, but for a few seconds every so often, the roughness is unacceptable, but it corrects back to the steady rough idle. Dealer recommended in addition of what i did, to reprogram the computer and to clean the intake. Any suggestions or ideas?:banghead:

 

[Jeremiah Morgan]

Any codes?

 

[Kevin Palmer]

Was it ruff before you made changes, or were the changes done because it was ruff?

 

[Makin Trax]

sounds like a clogged injector to me try a quality fuel injector treatment like somthing from lucas oil it's only like 5 bucks and could clear up your problem

 

[Dingo]

It's the computer.

 

[Ricky Soto]

No codes, no check engine light. The engine was idling rough, so i changed the parts i mentioned earlier. it got better, but it's still not idling like it should. It seems to run smoothly for a few seconds, then it shakes pretty bad, and tries to recover, but never quite gets to idle smoothly. after a few moments (can't define a time lapse) it is smooth as silk, and then it goes bananas again. I did the fuel injector treatment (last two fill ups) and it did not help. I guess it's time to re-flash the computer. Is that something only the dealer can do?

 

[James Kerr]

Try reseting the computer by disconnecting the battery for 5 minutes.

 

[scott degroot]

You changed all 8 ignition coils??? Or did you change the spark plugs?. As far as I know there is no flash for a rough idle concern. This is going to need to be diagnosed, you are going to need to know various sensor readings adn especially what the short term and long erm fuel trims are doing at idle.