He's not been back since these posts... maybe he sold it.. Rolex if you're having similar problems, suggest taking to an indy or the dealer and start with getting the codes read. What is your engine? Mileage details.. The BG Valve service (I think it's the induction) is a valid point, throttle body, and a bunch of other possibilities including MAF, O2 Sensors, Tranny, etc.

 

My $.02:

Clean MAF (remove sensor and soak it carefully)
Throttle body
BG 44k in fuel tank
Maybe trans flush
Induction flush
Fuel rail/injector cleaning (like RSW solutions does)

I have done the first 3 items and it helped some. Meaning to do the others. I just chalk up the sluggishness to the sheer weight of the vehicle, but I do get how freaking annoying it is to have off the line acceleration like a school bus. Using sport mode or command shift helps.

I typically use sport mode on freeway on ramps when I really need to move. Then command shift down when passing.

 

Well I took mine to the dealer. While waiting for a service advisor, decided to move the truck. Won't start. Nothing. Dead on the water. Dealer said they will check it for $400. I said no thanks and called AAA. Towing came and car started. Decided not to get it towed. Went to autozone had the battery checked. All is good. Drove the truck 55 miles to another dealer who charged only $160 to diagnose. Left the truck. They said they need to put a new battery on it since it won't start. Told the advisor I just had the battery checked and was fine. I said ok to new battery. They charged me $293 out the door for an interstate battery. They drove it 8 miles and they said nothing wrong with the truck. When I got the truck back all was working fine. On the drive home, after 25 miles of the truck driving perfectly, there it goes again, the feeling of the truck drowning in gas or multiple misfires at 1500-2000 rpm. Feels like stuttering. No codes. Changed MAF. Changed all 4 O2. Cleaned throttle body. Putted techron and seafoam multiple times. Any ideas?

 

Might be coil packs (if more igniton related)? I have had that suggested in conversations with my old dealer. That or maybe changing spark plugs? I honestly don't know too much about this problem area... you are using the LR3/Disco3 norm of at least 91 octane, right?

 

Yea i am using 93


I am changing plugs this week. we will see. what do you guys think about clogged cats?

 

Clogged cats seems pretty unlikely and far fetched compared to some other simpler explanations for loss of power and misfires.

When you say there were no codes stored, do you mean you checked with a generic OBD-II tool and saw nothing or did you use something like a GAP IID tool or dealer scan tool to check?

Basically, it boils down to fuel, air, or spark issues if you're having misfires and loss of power.

For air, the things I would start with are:
1. Change air filter
2. Clean MAF sensor
3. Clean throttle body/butterfly valve and/or consider fuel induction service (BG, etc)

For spark, I would:
1. Change the spark plugs
2. Totally agree with DavC, that it might just be a simple bad coil pack - need the engine code to diagnose which one though. If you can pull codes as to which cylinder is having the misfire, it might be a good idea to replace the coil pack on that cylinder.
3. New battery which it sounds like you've already done
4. Check ground cable from chassis to negative terminal on battery for continuity and corrosion. If the dealer replaced the battery, hopefully they already looked at this, but it's not uncommon for that cable to fail due to corrosion.

For fuel:
1. Fuel filter, but I don't think we have a serviceable fuel filter on the 4.4?
2. Fuel pump - worth getting the pressure in the system checked, but this is one of the last things I would do
3. Clean fuel injectors with a fuel injector cleaner (BG) - not just a gas treatment additive. (if you do this, do it BEFORE changing your spark plugs since it is very harsh on the plugs)

That's my $0.02 on the simpler things I would try first. I would be inclined to agree with DavC though that it certainly sounds like it could just be a coil pack acting up. I have to think there are some trouble codes stored in the computer though if you are really getting misfires.

 

UPDATE:

Today Changed all plugs. When I looked at the plugs they seem fine. but I was in there already so changed it.

Changed PCV Valve. Nothing still the same.

Checked Fuel Pressure

I am running out of ideas.

when you start the car it runs fine, after driving it 5 miles it starts acting up. no codes.

 

shoot.... what about the throttle body housing and the air intake? Are there any leaks in or past the area around the MAF? Hoses not sealed all the way? Maybe its the system freaking out and flooding the system with fuel because the MAF is being fooled?

EDIT: how hard is the plug change by the way? I have been meaning to get to that.

 

Plug change is pretty easy as long as your coil pack boot doesn't break off like mine did. The most difficult spark plug to get to is the driver's side closest to the firewall. IIRC, I needed an assortment of different size socket extensions to get it. Basically, I needed a longer one to unscrew it (6"?), then I had to take the long extension off and put a shorter one on in order to lift the extension + socket + spark plug out of the hole. Oh, and you'll probably need to bend the foil heat shielding out of the way a little bit.

 

Dave Plug change was a breez. just took me 30 min and I am a novice.

I had an indy shop smoke the car. nothing. two indy shops and 1 dealer dont know whats wrong with the car lol