I have my 2003 mustang gt. I was driving it a while back and it suddenly lost all power and currently has a rough idle, so I parked it and as I was trouble shooting it I noticed that the rear drive side cat was glowing red. I bought a bassani high flow cat system, changed the egr valve, the MAF. The cat does no glow a but it still has an erratic idle with an occasional misfire. Any advice would definitly help.

 

I almost forgot to mention that I changed the fuel pump and the fuel filter.

 

I think you might have a stuck open injector. Unplug 1 injector at a time on the driver side and see if the idle improves. Also check your spark plugs... factory platinum plugs work great one day and then instantly turn to **** when they're beyond some arbitrary threshold. I had mine go bad while driving to the shop... it was weird. Only would work at odd throttle angles and when the engine was already spinning pretty fast. New plugs and problem solved.

The cat glowing red means your cat is also probably trashed. Pull it off and make sure you can still see light through it.

 

The cat has been replaced, but the fuel injectors have not been checked. I have changed the cat system, fuel pump, fule filter, egr valve, maf and also checked the IAC. I will check the injectors.

 

I had a friend hel pme out today and he unplugged each injector and it did not do anything. He said that the engines sounds as if it is starved for fuel. He mentioned that it may be the fuel pressure regulator that is not regulating the adequate amoun of fuel.

 

It doesn't have a fuel pressure regulator if it's an 03.

It has a fuel rail pressure sensor which tells the ECU electronically the pressure at the rail which the ECU uses to tell the fuel pump driver module how much voltage to send to the fuel pump.

In any case, I think now you need to check and probably change your plugs. Replace them anyway if it's been >50K and they're stock. If they're stock or platinum tip it can be hard to detect a flaw. I prefer copper. In any case, if the car still runs like crap after a plug change then we'll move on to O2 sensors (the front ones are the only ones that matter) and then we can do a compression test if all else fails.

I'm pretty sure it's either the plugs or the O2's. I'd bet it's plugs (probably just 1 or 2) since you're not mentioning throwing a code. If you're showing a CEL (check engine light) then have the codes read (most auto parts stores will do that for free) and post them up. Those are terrifyingly helpful in diagnosing a problem.

Do you have an aftermarket tune on the car?

 

Just wanted to say that I followed the link on your stang and it looks freakin awesome. I had already changed the plugs to new NGK platinums. This is how everything went down. I filled the tank at a store, let the car sit for about 2 hours than drove a not even an eight of mile when it lost all power and was idling erratically. I had the fuel pump tested at the fuel rail and I was told that it did not have adequate pressure. So I changed it along wit th fuel filter (it was very dirty). Than the car still had the same symptoms and I looked under the car to see a clogged CAT, so i bought the Bassani high flow catted mid pipes. It still had the same symptoms so I cheked the plugs and they were covered in carbon. That is when I changed them, then I changed the egr valve guessing that it could be be faulty. Again no luck. So we reconnectd the scannertoit and it said at first that two O2 sensors were bad. Than we connected it again to double check and than it said the MAF and the IAT were bad, so i changed the MAF and the IAT is also intergrated the same component and that is wher I am currently at. I have a friend that let me borrow a good fuel rail pressure sensor. So I am going to hook that up and see what that does. I think that judging by the way the fuel filter was I am sure that the injectors are clogged. The car does not have an aftermarket tune.

 

You'll need to probably replace the front o2's. With that much carbon on the plugs it's probably fouled the o2 sensors. If you had an apparatus to check the flow of the injectors that could be something as well. I still don't think it's the injectors because it was so sudden and it wouldn't probably be all of them. I'm betting the ECU is either dumping asstons of gas in the tune or not enough (high carbon deposits on the plugs says asstons). o2's (and maf) are important for idle and part throttle driving but for WOT it uses the MAF and discounts the o2's (the o2's are narrow band so they couldn't tell the ECU if the AF is right, only a good tune can, thus it ignores them at WOT)

I want you to drain your tank and fuel lines all the way to the rails (empty the few drops from the injectors too) and refill (well... a few gallons at least) with gas from a different station if you have not already done so. That will eliminate bad gas or diesel contamination. I've had an experience of buying 91 octane and pumping 91octane and ending up with #2 diesel. It ran for a bit then went all to hell.

IN any case, next steps: drain fuel, refuel, check for carbon on front o2's (replace if needed), disconnect battery for 10 mins, attempt to start it. Then the LAST thing in my book of **** to do would be to replace all the injectors. At that point you'll have replaced most everything and I hate that kind of troubleshooting. I want to find THE problem for you before we get that far.

 

Yeah... thinking about it more, I'm pretty sure you put diesel in the tank inadvertently. Either you may have grabbed the wrong handle or they had some idiot driver put diesel in their gas tank.

 

That particular retailer does not sell diesel, I know because I work for the local Red Bull Distributor and I distribute to that same station. I can't vouch for the idot drivers that dump the fuel because some those guys are not the brightest guys in the world ( and they are driving flammable liquids). Anyway last night I went ahead and removed the fuel rails and I took off the injectors the fuel that came out was very grainy, felt like wet sand.I cleaned them really good with some carb cleaner. The first two on the driver side were completely clogged at the spray tips. The next two were partially clogged. Same thing on the passenger side, real grainy and sandy fuel. I am wondering if someone poured sand in my tank. I have pissed alot of ricers off, and I have a mean ex from hell. I really appreciate your help with this, aftert he car is fixed I will ship you a case of red bull.

 

I think it's sugar or salt... maybe sand. But it is grit. Blast it all to hell it was the injectors. Well, we have the answer. Drain the tank and the lines, flush the lines from front to back with the filter removed.

You're going to want to drop the tank for this. And get a locking gas cap.

 

common water will dissolve the sugar if it's sugar. You may end up replacing them. We'll see.