So about two years ago I bought a cheap running 2005 s type R. It's issue was the valley pipe. Therefore drove it in the backyard where it sat for a couple years as I slowly did work. Anyways a little history on this beauty.I took off the hoses and supercharger to get to the valley hose. No biggy.So 2005 STR 93k miles. Did a refurbish on the sc. Bearings, pulley upgrade, solid coupler, and took the flaking black powder coating off of the blades. Overall at idle the sc sounds scratchy and like marbles in a tin can.Almost all new coolant hoses, gaskets. Basically replaced things upon putting the car back together.New air filter, cabin filter, fuel filter, spark plugs.So my main issue is that when driving my top speed is 70mph.It doesn't get up to that speed as you'd expect either.When I go full throttle the car even went into limp mode for a few seconds and codes popped up on the scanner but I'm suspecting because of my dumb action. Those codes werep1313 and p0307 and that happened when I floored it into partial limp mode. Those codes shortly went away though.But there is a constant code p1000 that won't go away.I think if that goes away that more important codes pertaining to my issue will arise. I've had the p1000 code go away after some driving but this time it won't.Just wondering if anybody's ever experienced this.With ignition on the throttle body plate opens 100% on the scanner.also filled full tank of shell v power gasoline and it's drinking the fuel rather quickly.While running throttle opens to about 14% revving to the limiter (4k) in park.fuel pressure stays around 55psi while driving and when flooring it stays the same or I've seen at most 60psi.Any ideas or experiences or troubleshooting would be great.I thought this was a fluke since it didn't show in the main menu of the scanner during the initializing process but in another menu I found an OEM Enhanced selection and got a p1798 and p0706 codes for transmission.Also I'm in Ohio USA

 

You mention limited max speed, but what I think is that what you really have is an 3000rpm restriction, the so called limp mode...!?
This means that your Jag knows that something is pretty wrong, which needs to be fixed first before you can floor it again.
Codes P1798 and P0706 both point at the transmission. Funny that I just posted 5 minutes ago a reply-post on a thread, where the XJR just does not wanna run anymore after jumping a curb. What are the odds that you would have the same issue - the rotary switch (switch on the transmission):

https://www.jaguarforums.com/forum/x...oblems-192893/

 

That is and I'll check it out shortly.
And this issue will cause the vehicle to feel like there's a vacuum leak or fuel delivery issue?
Will unplugging the battery or throttle relearn maybe ghost fix the problem? Dumb I know but I've read about an xk8 owner getting lucky with his
Also just now read somewhere that the p1798 code could mean tranny fluid is burnt or contaminated.
But that was on a 97 xk8

 

Miracles can happen, when unplugging the battery - plus, charging the battery regularly also does miracles (I have 3 CTEK battery chargers).
Well, I just accidentally produced (an easy to solved) restricted mode a couple of days ago on my X-Type:
I could suddenly no longer exceed 3000rpm - nearing 3000rpm, the engine began to stutter (which could be interpreted/feel like a fuel deliver issue, I guess).

But quickly solved: I never have codes on that car. The problem occurred after I briefly removed the air filter. I connected a scanner and got 3 codes. The only code, which made sense was about the MAF. Hence, I then immediately had a suspicion what it was: I simply forgot to reconnect the MAF-connector to the MAF (Mass air flow sensor) just behind the air-box...

Any chance you forgot to put your MAF-connector back on?

 

Last time I forgot to plug in the MAF the car wouldn't start at all.

 

I played with the car today and now when I put the key into the ignition I hear bubbling inside the dashboard.
so I followed the sound into the engine bay and the sound is coming towards the back of the engine and smells like gasoline. 🤦

 

Are you sure that noise wasn't there always? Some of my Jags make funny noises, just all the time - ignition on and the noise is there. When you start the engine, the noise is probably still there, but the engine is louder.... The noise is coming from around the throttle at some Jags, at others from the dashboard.
But a smell of gasoline is of worry. I don't have many ideas there, other than a leaky seal in the fuel line.