Hello all, I just bought a 2002 STS V8. After getting her home and she was running pretty rough so I changed the spark plugs and checked the coils. Everything was fine except that the old plugs were low cost autolights. So I changed all the plugs to the correct Bosch double platinums put her all back together and fired her up. Now she idles smoothly however she’ll only rev up to 3000 RPMs. I used my handy dandy code tester and found “No Codes”. I let her warm up and tried the gas again, still only 3000 RPMs.
I’ve looked all over the forum and couldn’t find any references for this problem. Please help.

Alan

 

Are you driving the car or just revving stationary? If stationary the revs are limited to 3000.

 

Yes just stationary, it is my first Jaguar so I’m a new parent. I’ll take her out and see what she’ll do. Thank you so very much, I was pretty worried that it might be beyond my abilities to repair. And we all know how much shops charge lol.
Again-thank you so very much for the quick response.

Alan

 

I thought an STS was a Cadillac?

 

No there is a 2002 V8 Jaguar STS. I think it stands for S Type Sport

 

Not generally abbreviated to STS, but it's not a crime

 

I’m just quoting what it says on the title

 

Can we presume this was the issue?

It's not uncommon for vehicle manufactures to limit unloaded RPM limits.

 

Well it’s been raining here so I haven’t had a chance to take her out yet. She fires up and idles just fine now. The new platinum plugs I put in seem to have fixed the rough idle problem, no miss fire or stumble when I press the gas. I’m waiting until they come out to fix the driver’s side window and for the rain to stop before I road test her again.
Thanks for all the replies, I’ll keep you all posted.

Alan

 

Me too.