Now mind you I just got the x300 back from the painters (I know, I know--pictures ) and I have really only been driving it daily since this past saturday, and I know the car is 15 years old as well as my first Jag, but--I noticed this noon when I started the car it would catch-start-then the RPMs would dip-then pick up-and run fine. After work it seemed to start fine, but when I backed out and stopped to go from the reverse to drive she stalled. Started her up just fine and drove home. Once I was safely in my drive way (beer in Hand) I started her up 6 times in a row with 5-7 minutes between starts. Started fine, a couple times she cranked over for about 3-4 seconds before she caught. Sound familiar to anyone? Beginning of a problem, or just in need of a good tune-up? Chime in with any ideas and thanks----Scott

 

Crank position sensor packing up? When it doesn't start the rev counter won't move to 150-200 rpm upon cranking. A good CPS will register as 150-250rpm upon cranking.

 

Might also be auxilliary air valve (or whatever it's called on these cars). Although this problem usually surfaces when you approach a junction and the car stalls. Worth checking all vacuum pipes also.

 

I will check my vacuum lines. I need to watch my RPM gauge closer when I crank the car to see what it is registering. I am in the process of ordering my x300 materials (parts, service manual...etc.) from Paul's Jags out of Florida so that may help me a bit. Thanks for the lead on the CPS---is that a difficult part to change out?---------------------Scott

 

Never had to change one on these cars - yet. Doubt it will be too difficult though. I'm sire it sits near the crank pulley on the block. Usually a plug at one end and one or two smallish bolts (10mm is a guess) at the block end.

 

drove the car this afternoon and sat and started it a few times. Started just fine. Watched the tach and she turned over at 300 rpm before starting. Maybe it was just a thing--stuff happens. But I will keep my eye on it. Your right straight6, I did some investigating and the CPS is located towards the front on the timing cover. Looked simple, unless you elected to change the ring gear at which point it was a little more complicated, but still doable if you had the right tools---pulley pullers...ect. thanks for the help guys

 

Mine sort of does the same thing but it has never stalled out on me. When I crank it it stays at about 1000 to 1100 for about 2 seconds then dips real quick to about 400 to 500 before it idles at about 800. Think its the same problem?
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