2003 LS V8 lot of noise under car, won't run

[sventure]

Was having trouble with MAF and coils. Replaced, ran great. Then all of a sudden, car started making a lot of noise under neath, backfiring really bad and won't run good enough to back out of the driveway. No check engine light!! I'm stuck. Any ideas?? Could really use some help.
Thanks.

 

[AmsterDutch]

Was having trouble with MAF and coils. Replaced, ran great. Then all of a sudden, car started making a lot of noise under neath, backfiring really bad and won't run good enough to back out of the driveway. No check engine light!! I'm stuck. Any ideas?? Could really use some help.
Thanks.

Are the Cats plugged up? How long did the car “run great” ???? Is the fuel pump working properly? Are all vacuum lines connected and not leaking? What brand COP(s) and plug(s) did you install? What scanner are you using? a check engine light doesn’t have to activate to trigger a code always ....Have you disconnected the battery at all?

 

[sventure]

Not sure about the cats. How do you check them? What happens if they are clogged? Ran great about 3 weeks. Fuel pump is good, no vac leaks. Don't remember the brand of COP but got them from Advance Auto Parts. I don't have a scanner and I have disconnected the battery.

 

[joegr]

...Don't remember the brand of COP but got them from Advance Auto Parts...

Classic mistake. Read the forums. Also, you will get more responses if you move your post to the correct forum. Lincoln LS is the place for general questions problems. This forum is for people trying to modify their LS for higher performance.

It really needs to be OEM coils. You can remove your front two O2 sensors (temporarily) to check the cats. This lets the exhaust escape if the cats are clogged. You are going to have to have a good scan tool to work on this car. Forscan seems to be a good choice.
How do you know the fuel pumps are good? Did you measure the fuel pressure? If not, then you don't know.

 

[SHORod]

Are you sure that you got the MAF sensor electrical and intake air hoses connected properly after working on it? Unmetered air (air not passing through the MAF sensor) getting in to the engine can cause the symptoms you describe as well.

-Rod