2003 Lincoln Ls won't rev up while driving

[greenee179]

I was looking at buying a 2003 Lincoln ls with 108k miles. The owner says while driving it, it won't rev over a certain rpm point like its leaning out. They've replaced all 8 coils, new fuel pump,new fuel filter, new tps,and cleaned the maf sensor. He said the car ran fine before sitting a year so what would cause this issue? Oh also it reads no codes.

 

[joegr]

Unfortunately, there are a number of possibilities. Also, I'll bet there are codes present, you/they just aren't using a scan tool that can pull them.
My first guess at this (based on the very little bit of information provided) is that the cats are clogged from waiting too long to change the coils. (I really hope they replaced the spark plugs at the same time as the coils.) You can test this by removing the [forward] O2 sensors. The holes where the sensors were will allow enough exhaust out to make a noticeable improvement if clogged cats are the problem.

 

[RigsLS]

Not forgetting about that year old fuel which is pretty near done by now if stabilizer wasn't used, Garbage in = Garbage out.
But yeah, clogged as Joe suggests, can't breathe properly.


Breath definition, the air inhaled and exhaled in respiration :shifty:



PS: Joe!

.... You can test this by removing the [forward] O2 sensors. The holes where the sensors were will allow enough exhaust out to make a noticeable improvement if clogged cats are the problem.

There is an easier method of testing this. Very cost effective also.

1) Get wife to put her lips around the tail pipe.
2) Start the LS, no revs, just a turn over and shut down.
3) If the wife gets up, CAT is clogged.
4) If the wife does NOT get up, lucky sumbitch, your CAT is NOT clogged!

- Repeat test on other tail pipe.

 

[greenee179]

Oops sorry I forgot some of the info he told me its the 3.9L v8 also they changed the spark plugs, and suspected the cats were clogged so they gutted them out, but that made no difference.

 

[joegr]

Oops sorry I forgot some of the info he told me its the 3.9L v8 also they changed the spark plugs, and suspected the cats were clogged so they gutted them out, but that made no difference.

Could be an issue with the electronic throttle. Is the check engine light on? Did they gap the plugs to 1.0mm? Did they use Motorcraft coils? The issue is likely to be a minor one, but finding it could be very involved. If you troubleshoot by throwing parts at it, it could get pretty expensive.

In other words...
If you know the LS, depending on the asking price, it could still be a good deal.
If you don't know the LS well, then I strongly suggest you pass on this.