Petrol smell exhaust!.
 

I noticed there was a bolt missing on a air intake which i think is where the mgr valve is located. There was a gap between the hose. So I put a bolt in and closed the gap in the pipe. The day after I started the car and it ran rough and cut out. It would not restart so called my breakdown company and it was flooded. So they sorted it out. Now I can smell a petrol smell from the exhaust. It sometimes stutters slightly when I put my foot down and sometimes tries to cut out when first starting. But it seems to run smoothly. It seems to use more fuel also. I was thinking maybe a spark plug is not working but not 100% sure. I get a error code p1646 on my diagnostic tool which I have got since getting the car. Any suggestions would be greatly appreciated.

It's not a spark plug on the blink, it's an A Bank upstream O2 sensor, probably dead. Their job is just as harsh as a spark plug and wear out leading to fuel trims out of wack. If you change it yourself you will need an O2 socket or kit to remove it.

Can you post a picture of the bolt in the tube?

Even a tiny leak will cause big trouble but first fix that O2 issue.

It's a good idea to have an OBD tool that can show live data and look at LTFTs - after doing the fix - to see if they're OK.

If you can smell petrol like that then it's flooding the cat(s) and may well be destroying the cat(s) so avoid using the car till it's fixed - cats are costly!

Bolt!.
 

Here is the picture of the bolt I replaced. I am just wondering if it was left out and there was a gap left in the air intake hose for a reason. It's just after putting the bolt and made there was no gaps the problem started!. Also on my diagnostics tool it passed on everything except components.
https://cimg5.ibsrv.net/gimg/www.jag...4169d00aa4.jpg
Error Code!.

https://cimg2.ibsrv.net/gimg/www.jag...d329d9710d.jpg
Air inlet!

Do a hard reset so that the ECU can return all the settings to nominal. Disconnect the neg. cable from the battery and touch it to the positive post for 20-30 seconds. When you reconnect turn the ignition key on but don't engage the starter for 30 sec.

^ This, if you change the amount of air going into the engine, you change the fuel mixture. Unmetered air leaks are a devil. Performing a 'hard rest' as RJ suggests puts the car back to factory engine map settings, and from there it will learn and adapt a new fuel map for the metered airflow.

Carry out the hard rest and start the car, it should have a high idle (1500rpm+) initially, then decays back to almost stall point - this is the engine ecu performing a throttle calibration, once this is completed let the car idle for 10 minutes then take it for a drive, any codes after clearing before said drive, post here.

I think you had an unmetered airleak, the car's ecu added fuel to compensate then you cut the air by fixing the leak, but the map is still overfueling - this could cause an O2 code.

Removed the battery!.
 

I did not have the courage to do a ECU reset. I was worried about getting any issues after. I removed the battery for 10 minutes. When I turned it on it acted like I had one a ECU reset. Because the revs went high then it tried to stall. The 1646 error code did not appear after taking it for a drive but it appeared again shortly after. It is reporting a lot better range and mpg on the dashboard readout. It also surprised me that it never forgot my radio stations but I had to enter the radio code.

Change the O2 sensor and get even better gas mileage.

Ecu Reset!.
 

I reset the ecu today so will see how it is over the next few days.

Removing the battery for 10 min. probably resulted in a ECU reset, so don't expect much change. It's just to drain the capacitors.

The breather tube going from the intake pipe to the valve cover cracks very easily and can suck air. Every one at the junkyard I come across was broken, until I ran across one with NOS Jaguar stickers still on it (like it was just changed before the car was wrecked).

Disturbing the intake pipe a little could open a gap in the tube.

Rough idling when starting from cold!.
 

The same error code returned after doing the ecu reset. Also it's the same problem as before. When you start the car it runs rough like it's misfiring and tries to stall. When you put the throttle down it clears and does not stall. Then it drives fine. It only does this when first starting the car not when the engine is warm still.

Car starts ok but stutters when put foot hard on the throttle!.
 

The car starts fine and does not run rough anymore. But when I put my foot hard on the throttle the car stutters like it's not getting enough fuel.

Did you change the coolant sensor yet its cheap enough. no need to drain coolant just unplug it put a rag under it then remove old one then screw the new one in, very little coolant loss. coolant sensor is overlooked most of the time. A new one make a big difference to running smoothly