The past few weeks have been a journey with my truck. It's an 04 Disco with 116k miles on it.

It all started with it not turning over / starting occasionally about three weeks ago and with how it sounded and from reading here on the forums, I was led to believe it was the fuel pump. I ordered a new one, tested it and dropped it in. I also tested the old one after taking it out and it did work but the pull was considerably weaker than the new one. After a few days of driving it happened again. It wouldn't turn over after driving to the grocery store. After more reading here on the forums, I replaced the crankshaft position sensor over the weekend and it was starting smoothly but I didn't take it out for a drive. That now leads me to today. It started just fine and as I was driving to work it wasn't responsive on the gas pedal. As I was giving it gas the engine wouldn't respond for a few seconds and then it would rev up and go for 3 - 10 seconds of normal driving before doing it again. My commute is ~4 miles and I took back roads to keep my top speed under 40mph. When I got to my office I turned it off and tried to start it up again and it struggled before turning over and stayed at a calmer than normal idle/RPM.

Attached is a video of it surging while driving 20mph. I haven't driven it since.

At this point, I'm not sure what to think. I'm not mad about changing out the fuel pump and CPS (nice to know I have new ones in there) but I'm struggling to understand why my troubles went from it not turning over occasionally to now it still struggling to turn over with a surge to the engine. Any feedback and suggestions are more than welcome.

Thanks!

 

Video wouldn't upload properly so here is a link to watch it on Dropbox: https://www.dropbox.com/s/3705v4f7g7..._0930.mov?dl=0

 

Quick update if anyone is interested. A local land rover friend mentioned that I could be low on gas and my new fuel pump just isn't reading it properly. It took a few turns for it to start up and I got it to a gas station with no bucking or surging on my way down the road. Gave it some gas and it's been running smoothly since but it still lags to start. I'm worried that it's only a matter of time before it doesn't turn over and I'm stuck somewhere.

Going to keep an eye on it and drive short distances over the next few days. Open to any suggestions here.

 

First off, are you showing any codes?

Things I would check in the order that is easiest:
1) Battery voltage
2) Throttle position sensor
3) Idle air control valve
4) MAF sensor
5) Fuel pressure
6) Injectors

 

I don't have any codes but I can take it by my local shop to pull them. After installing the fuel pump two or so weeks ago, no lights have come on in the dash.

Thanks for the list. The battery is about 9 months old and we tested it when installing the fuel pump. All good there. I'm going to start working my way down that list and I'll keep you posted.

Thanks again!

 

fuel filter clogged? How did the inside the tank look? Dirty/clean? Had exactly the same issue with a different vehicle. Ran fine, then out of nowhere loss of power and hit or miss throttle....Particles would clog filter depending on slosh effect.....

 

I was thinking the same thing but the tank looked very clean when I dropped in the new fuel pump and the old pump's filter looked pretty clear as well. Past two days it's been running great once it's on and now just lags to start. Takes at least 2 - 3 tries for it to turn over but it has started every time I've needed it to lately.

 

I think there is a way to get a fuel pressure gauge onto the fuel rail test port at rear of rail...then you could test pressure when starting at least.....and see if it holds pressure overnight. It may be the pump pressure regulator, even in a new pump....

 

There is a Schrader valve on the driver's side((U.S) rear of the fuel rail, facing toward the firewall.