Mass Air Flow -- Or Fuel Pump?

[KAIN81]

Hey All - the '03 LS V8 is giving me a bit of grief but I think I may have it pinpointed to one of two things. Either the Mass Airflow Sensor has to be cleaned (possibly replaced) or the fuel pump is on it's way out.

Symptoms: car chokes/hesitates on acceleration between 1 & 2,000 rpms , and is 100x worse when the AC is one. Once past 2,000 rpms it runs smooth. The issue has gotten progressively worse, but has been happening sporadically now for 3-4 months, which leads me to think it's the Mass.

Fuel Filter was replaced 20K miles ago. NGK's were installed about 30K ago. Air Filter is new. Oil Change is up to date. Fuel Injection Cleaner is run at every oil change and only 91 Octane is used. Car is babied.

Any and all help is massively appreciated!

And here's a pic just for fun - just had the tint redone all the way around.

 

[Blueberryyum02]

Coils: when was the last time they was replaced.

 

[joegr]

Yes, it is very likely marginal coils (COPs). The best advice is to replace them all (at the same time) as well as all the spark plugs. The sooner you do this, the better.
If you want to eliminate the MAF from your suspicions, then unplug the electrical connector to it. The PCM will go to default fuel values. If the MAF is the problem, then it will run much better. If not, it may still run a little better because the mixture will probably be richer.

 

[KAIN81]

Coils: when was the last time they was replaced.

Never - only the plugs were done , car has 130K on it.

The plugs were upgraded and replaced about 30K ago.

Is there a way to pinpoint the coils as the issue?
Found good pricing on Rock Auto - any suggestion on which brand is the best for the dollar?

Thanks guys.

 

[Blueberryyum02]

The only way I know of testing the coils is a stress test. But like Joegr stated just replace them all.

 

[joegr]

...Is there a way to pinpoint the coils as the issue?...

Yes, a stress test.
http://www.stangnet.com/images/stories/docs/s197_TSBs/04-16-1.pdf

This will cost you as much or more as replacing all the coils yourself, and you could still have more fail in another month. 130K on a set on coils is more than most here have managed.

 

[KAIN81]

Yes, a stress test.
http://www.stangnet.com/images/stories/docs/s197_TSBs/04-16-1.pdf

This will cost you as much or more as replacing all the coils yourself, and you could still have more fail in another month. 130K on a set on coils is more than most here have managed.

Full replacement it is then - any suggestion on which brand to order? Rock Auto 10 different manufacturers.

 

[joegr]

Full replacement it is then - any suggestion on which brand to order? Rock Auto 10 different manufacturers.

My suggestion is to get Motorcraft. Also, even though they are fairly new, you should replace the plugs at the same time.

 

[1LoudLS]

My suggestion is to get Motorcraft. Also, even though they are fairly new, you should replace the plugs at the same time.

the main reason being, a bad coil can damage a plug, and if you dont replace that plug, then the damaged plug can damage the new coil...