Hello guys, posted on this before;

My car feels heavy out of stops. Heavy and underpowered. I thought the brakes where sticking but now I have new calipers and hoses and still have this problem. This is not a sticky brake problem. The car will feel heavy and underpowered out of stops on heavy traffic and stop and go conditions. Sometimes it feels like it does not want to get in gear after a stop, or if I slow down to go over a speed bump. if I am going faster and have to come to a dead stop and then quickly accelerate again, the transmission gets confused, the car revs and it takes it moment to catch up. The problem seems to be fuel related as it seems to go away when the tank is full. The car also sometimes shakes when I am driving, let go of the gas and then accelerate again (although that may be the propshaft)

So far I have:

Changed fuel filter
Changed spark plugs (with correct Autolite)
IMT o rings and manifold gaskets
Cleaned the throttle
Cleaned the MAF
Changed the tranny fluid out several times
Checked the TCM for water ingress.

Mechanic has changed calipers, hoses tested e break, and bled THIS IS NOT A STICKING CALIPER SITUATION.

I don't think this is a transmission problem I am having. I think it's fuel related, although I found a post out there about a member who solved his heaviness problem with a new drum and clutches and another who replaced the valves on their transmissions and solved their heaviness problems.
I have had two different tranny shops look at her and drive her and they could not find a problem.

I have posted on this before, but I am really irritated that I still can not solve the problem. My MPG is still terrible.

Any help is greatly appreciated !

 

Have you considered the lambda sensors?

Symptoms of a Faulty Lambda Sensor | eHow UK

Poor mpg
Unusual lurching / hesitation
decreasing engine power at cruising speed

Had similar issues on my sons Clio and mo other sons Astra, and this turned out to be the problem.

I'm assuming you have no CEL showing? Have you done a diagnostics test?

It may be worth checking, at least to rule it out if nothing else?

 

Could be a problem with fuel trims. Think I'm right in saying that if you disconnect the battery for a minute or so then reconnect, they will reset as the ECU relearns its settings over a drive or two over a few miles.

 

Air Filter?

If it was just a bit dusty and then got wet, it could look fine, yet be like breathing through a brick. Just remove it and try driving a mile or two, see if any difference.

 

Spike, I would say to first start off with measuring the fuel pressure when the tank is near empty. It is possible that you are starting to see the fuel pump go and it is aggravated by the loss of suction pressure from the full tank as compared to the empty tank. When you attach the fuel pressure gauge, it should read up near 50 psi (40-50 psi) when the engine is off and near 40 psi (30-40 psi) with the engine running at idle. You can try revving the engine and what you should see is as you step on the gas, the fuel pressure will drop slightly few psi, then go up by about the same amount. If you start seeing the fuel pressure drop significantly when you step on the gas to raise the RPMs quickly, then this is a sign the fuel pump is starting to go.

The other thing that I would say to try is to switch to a different big name brand of gas and run a tank of that. Slightly different detergents and it will help clear up an injector issues. you can try running a bottle of injector cleaner, but make sure that it is not made by the same people you currently buy your gas through (ie, if you get Chevron, do not by the Techron cleaner). Lets see what you have then.

 

Spike;

Replace the muffler bearings.

The transmission confusion, fuel problems, shaking, and all your vague and subjective problems from previous posts will be resolved by replacement of those bearings.

 

Thanks so much for the replies.

Bruce and Astromorg; the filter is new and the battery has been disconnected more than once.

Jim; the light is not on. I will look into the O2 sensors.

Thermo, the fuel pressure was measured by my mechanic and he said it seemed fine. I use either Chevron or Shell premium. I can try Exxon next.

Big diver, please tell me a little more about these muffler bearings ? Where are they? I haven't heard of these before

 

Just a thought Mark, but have you checked the EGR. May need cleaning also.

 

Spike, ignore this *****.

Urban Dictionary: Muffler bearings

 

 

Thanks everyone for the replies. I should have figured themuffler bearings reply was a joke. Thanks Matt and DPK for pointing it out(otherwise I might still be looking for them).



Jim, can a dirty EGR valve cause my symptoms?

 

Not quite sure Mark, but with your symptoms combined with bad MPG and the fact that it hasn't been mentioned, is it not worth a look.

I've seen lots of posts about lack of power with reduced MPG and most go for the EGR.

That was my thinking.

 

Like Thermo said I could see this being a fuel pump problem too, kinda makes sense that if the fuel pump cant/isn't keeping up with the needs of the injectors you'd get hesitation issues. I hope not though, for your wallet's sake.

 

Thanks everyone for all your replies. My mechanic just called me on the total bill onmy XJS to do some brake work and replace all 4 rear suspension mounts (everysingle one was broken), and now the E-type has to go in for some work I cannotdo myself as well…..point is, I am going to have to try to tackle my X typeproblems on my own:

1-How hard is it to get to the EGR valve? Has anyone cleanedtheirs, or should I order a new one? The one on my XJS needs periodic cleaningand it’s easy to get to. Hopefully I don’t have to take the car apart like Idid for the spark plugs.

2-The O2 sensors—wouldn’t the car be throwing a code ifthese where bad? Has anyone had luck just changing them on a hunch?

3-Fuel pump-are there two for this car? ………..I recallreading there are 2 pumps for this car. Is this a common failure? Car has 67Kmiles…



Thanks all!!

 

At that sort of mileage I wouldn't be surprised if it may be one or more of the 02 sensors.

They can be failing ( borderline tolerance ) and not throw a CEL but there may be a code if you have access to a code reader??
Deffo worth getting it read to check.

Going to a dealer will cost you plenty to diagnose, supply & fit IF this is the problem.

You can alternatively buy these yourself for much cheapness, they are fairly easy to remove and replace yourself.



If yours is the 2.5 or 3.0 I believe there may be 4 on your vehicle ( worth checking )

O2 Sensors

General Information


The Jaguar X Type is fitted with 4 O2 sensors one up-stream and one down-stream on each of Bank 1 and Bank 2 in line with OBDII requirements. The up-stream sensors are located on the engine side of the catalytic converter, these are the main sensors for control of the fuel air mixture. The downstream sensors located on the exit (non engine) side of the catalytic converter performs the diagnostics for the OBD system.

Bank 1 sensor 1 and Bank 2 sensor 1, measure the oxygen content of the exhaust gasses as they enter the catalytic converter, the level of oxygen in the gas mixture is directly related to the 'burn' efficiency of the engine, it is converted to an electrical signal and fed back to the Engine Control Unit (ECU) to alter the fuel air mixture supplied to the engine.
Bank 1 sensor 2 and Bank 2 sensor 2, measure the residue oxygen content of the exhaust gasses as they exit the catalytic converter, this is used by the ECU to diagnose the overall effency of the combustion process and as part of the OBDII system it's measurement signal will be used to help identify combustion problems within the system.
The ratio of fuel to air in the combustion chamber is identified with the Greek letter 'lambda' hence the term 'lambda sensor' as the name given to the O2 sensors used in vehicles. Ideal combustion of gasoline occurs when the fuel : air ratio is 14.7:1 (fuel is 6.8% of the mass of the mixture) at this point the lambda value of 1.0 is assumed. As the lambda value drops the fuel:air mixture is becoming richer (less air more fuel) and conversely as the value rises the mixture is becoming weaker (more air to fuel).

With the engine up-to normal working temperature, check the output of the sensor wire, normally black with Zirconia sensors, you should expect an output of 0.2 – 0.8 volts fluctuating between these reading approximately 2 – 3 times per second. If the output voltage is lower than this, i.e. 0 – 0.2 volts there will be a lean running or excess oxygen problem. If the voltage is higher than this, i.e. 0.8 – 1.2 volts then there will be a rich running or excess fuel fault.


See link to powertrain codes below, that you may find useful..

https://www.jaguarforums.com/forum/x...des-faq-18395/

Here's a thread on this forum currently running, sounds quite similar and worth reading perhaps?

https://www.jaguarforums.com/forum/x...1-14-a-102582/

Please try and get a code reader onto the car to find further info if you can.

 

You can also go to advanced auto or autozone and they will scan your car and print you out any codes for free.

 

Oh, I forgot to mention, I have a OBD2 scanner and real time reader. There are no codes stored

 

When you say your gas mileage is horrible, can you elaborate? Just what is it? And what kind of driving do you do? Are most trips in stop and go traffic just a few miles or is your daily commute 20 miles on the highway? Those kinds of factors can have a big difference in your MPG. In probably 65/35 city/highway driving I'll get about 20-21mpg. In an all highway drive of any length I will average about 27.5 or so depending on the temperature. I have a 2005 3.0 lite with a manual transmission.

When you say the car shakes when you take your food off the gas do you mean a shake in the steering wheel like an unbalanced wheel would make or do you mean a shake like the engine is about to kill?

I know you have been battling this issue a long time. Maybe it is time to take it to another mechanic and leave it and have them drive it a few days so they can get a feel for what might be happening as opposed to having someone just look at it for a short amount of time. Hope you can finally get a resolution to this soon. Good luck!

 

Excellent questions. I will try to describe as best as I can. My commute is 15 miles one way, no highway driving, for lunch I drive less than 8 miles. My MPG is about 13-14.

The vibration is neither the wheel nor is it the engine about to die....its not a horizontal vibration but rather vertical, if that makes any sense. I let go lightly of the gas and it shudders and then I punch it as its decreasing in speed and it shudders again.

Thanks

 

That mileage does seem a bit low, but I wouldn't necessarily think it unreasonable either, especially if there is a lot of stop and go on that commute and if you accelerate somewhat briskly from light to light. These cars aren't the best city commuter cars when it comes to fuel mileage.

As for the vibration. when you say "it" shudders after lightening up on the accelerator, what do you mean? You feel it in the gas pedal? The steering wheel? Seat of your pants? Is the whole car bobbing up and down in a vertical motion? Does it feel like a mechanical vibration like if something is worn out in the suspension or drive train? Or more like something in the engine like it is hesitating or starving for fuel? Something else? The more descriptive and specific you can be maybe the more likely someone can maybe offer a different suggestion for you.