My car just started to pulsate and slightly hesitate when driving bewteen 40-70mph and the RPM's are under 2000...

IE...As I'm getting on the highway, while on the on ramp, slowly gaining speed to merge with the traffic, my car begins to pulsate and slowly jolt as I'm giving it more throttle. It isn't noticeable until after 2nd gear and as the car shifts into 3rd around 40mph and the revs are under 2000. As I begin to give it more gas, this is when it begins and pretty much stays steady up until I reach 70mph...

Has anyone else ever experienced this or heard of something like this...I've read through many of the threads and tried searching but nothing has come up...I have read about the 'lurching' but that is only in regards to coming to a stop...

Any info is greatly appreciated....

 

What year is your car. V6 or V8? I assume it is an S?

 

Sorry, I should have stated that...It is a 2003 S Type R...It has around 49K miles...

 

It's in his user name but shouldn't it be 400HPTypeR?

 

From...http://wikicars.org/en/Jaguar_S-Type

The supercharged S-Type R joined the lineup in 2003. The "R" is powered by a supercharged V8 producing 390 hp (291 kW), and can go from 0 to 60 mph in 5.3 s (0 to 100 km/h in 5.6 s). It includes 18 in (457 mm) wheels, wire mesh grille and dramatic monochromatic paint. The R also has a sportier front fascia with fog lamps built-in, a rear spoiler, a brace located near the rear subframe, and "R" badging on the rear deck lid and both front fenders. It is the most expensive S-Type, with a base price of US$58,995.

Jaguar first stated that the R made 400HP...but the ZF gearbox actually does not allow it to make that full amount of power and put it down thru the wheels, due to it's gearing and shift patterns. Jaguar addressed this in the '06 models I believe, as they are able to put down the full 400HP.

 

Does the check engine light come on at all or blink a little?
From the sound of what you are saying, probably needs a coil or two. Hard to say without driving it.

Also, there may be water ingress into the TPS. There is a bulletin to install a patch under the cowl to prevent water dripping on it.

 

do you get a restricated performance light on..?
agree with FJT may need a coil.

 

The check engine light is not on and does not blink at all...which I thought it would be on by now...

I take it you are referring to ignition coils??? Are they expensive???

And TPS???

I really appreciate the help...TIA...

 

Like I was telling FJT, there are no lights on the dash...

I did forget to mention that the car does squeak a little when it is cold outside and is first started...and never squeaks again once the car has been warmed up and driven...now that the temps are getting warmer it really doesn't do it at all...I was figuring it was either a belt or water pump, but I guess it could be related...

Thanks for the help...

 

THere is a bulletin for the squeek. Replace the idler pulleys and both belts.

TPS - Throttle position sensor.

You need to get codes scanned for free at autozone or somewhere similar. Let us know what is found.

 

Are the TSB's covered under warranty or if the car is out of warranty, are they still covered??? And I didn't know that Autozone scanned codes for free, thanks for the headsup...

I'll be interested to see if codes show up since no warning lights are on...

It's really quite great that you spend your time on here helping members...it is definitely appreciated, especially in this day and age...

 

THanks for that.

TSBs are covered while car is under warranty. Not once expired.
Only recalls are covered for life.
Let us know about the codes. It can stored them without the light coming on.

 

FJT,

I had the car scanned...a code did come up...P1111...Air Measurement Meter???

So I'm wondering if this is the 02 sensor or has something to do with the AFR...

Obviously you'll know...TIA

 

The P1111 is a readiness code. Shows that all the ecm has checked all the sensors are online basically.
There should be another code.

The Jag tool would be more effective at this point for reading the stored codes. Autozones cannot do it.
The thing is, most OBD II codes are two trip things. So if the code is set, the light wont come on for two drive cycles. If on the second cycle, it doesn't see fault, it will clear light out.

This is tough not being there for that one. I would drive the car get it hot, then at idle disconnect and reconnect the coils one at a time. See if the idle changes. You need to get it while it is acting up.

Where are you located? May just need injector cleaning.

 

Thanks...

After I looked into the P1111 code, I found out that it is just a readiness code. I guess what Autozone's OBD II reader said, 'Indicated Air Measurement Meter' is just specific to their OBD II...

I was wondering if it had something to do with the AFR because it seems like I am getting worse mileage...but just about any issue with the engine is capable of creating that...

That's what keeps on getting me, no warning lights whatsoever and the car runs and idles fine except for the 'pulsating' at the indicated RPM's and speed.

I am located in Cincinnati...the car just turned 49K miles, not sure if the injectors have been cleaned before or is it part of the upcoming scheduled maintenance???

 

pm your last 6 on your vin perhaps he'd (FJT) be nice enough to see what work has been done or if the pulley has been replaced...

 

The injector cleanings are not a part of a scheduled maintenance. There are things I would do first before going after bigger things. Especially with no light on. First, ECM reflash. The reflashes can cure many minor running conditions. Next the injector cleaning. I mean a real one, not just putting an additive into the tank. Next I would look at the coils. They can start to break down and not flag a code.

Start there and see what happens.

 

my car does the same and its an 01 S type 4.0
im pretty sure its my coils, it jerks at a red light too......its hard to narrow down which one of the 8 coils to change and I really dont want to spend $90x8 for coils....

 

Cheaper from Ford dealer. Same coils.

 

^ from what car?