Help not sure whats wrong

[phase_one]

My 2002 ls with 3.9 backfired. It broke the latches on the air box where the filter goes. It starts easy and run well at high rpms, but bogs down and kills at low rpms. The evenning before the check engine light came on, but I havent investigated what the code is. Any thoughts?

 

[myfirstlincoln]

What do you mean it kills at low rpms? How did it break the latches off the air box?? Are you sure it was a backfire?

Get a code scanner and check the code or bite the bullet and have it scanned at a dealer.

Could be a lot of different things. I haven't heard of a backfire like this due to a bad coil but coils are always trouble. However, if it's running ok at high rpms then you may want to look else where - could be something wrong with your fuel system

 

[pragmatic]

You need to check the codes. There may be several problems.

First why if backfired (and that's a true backfire, not the typical exhaust popping called backfire by many). Bad ignition timing is usual cause (rare now with computer controlled ignition). Spark is way early and occurs while the intake valve is open igniting fuel in the intake manifold.

Now it won't run at low rpm because the MAF sensor was damaged by the backfire.

Check codes first.

 

[cammerfe]

You need to check the codes. There may be several problems.

First why if backfired (and that's a true backfire, not the typical exhaust popping called backfire by many). Bad ignition timing is usual cause (rare now with computer controlled ignition). Spark is way early and occurs while the intake valve is open igniting fuel in the intake manifold.

Now it won't run at low rpm because the MAF sensor was damaged by the backfire.

Check codes first.

Good thinking!

KS