Hi All! This is my first post and I want to thank everyone already for the posts that have helped me out!

I have a 2005 S-Type R, Supercharged 4.2L Jaguar with 145,000 miles. I was driving down the interstate and all of a sudden it started cutting out and would not drive over 20 mph and it didn't want to stay started. It was needing a tune-up so I figured it was time to replace the plugs and all 8 coils. That did not solve the problem. Error codes displayed O2 sensor errors and a Mass Air Flow Sensor error. I replaced the Mass Flow Sensor and the 2 O2 sensors before the CAT and the engine purrs again! Yayy! BUT when I rev the engine to exactly 4500 rpms it begins to cut out and will not go any higher. Respectively when I drive 80-90 mph it begins to cut out the same. When at lower rpms it run great!

I cleared the codes and have driven about 50 miles and the engine light still does not come on. The last codes I cleared were: P0171, P0101, P0174, P1316, and P0300-P0307.

Also at one point I had taken off the air duct that goes into the engine. I did not put it back properly and the engine ran so horribly it would not stay started. When I put the air duct back on properly it ran fine again.

Any ideas as to what can cause the problem at 4500 rpms? Have I not put the air duct back on fully? Should I replace the other two O2 sensors? I would appreciate any help.

Thanks!!
Lewis

 

In park and neutral there is a rev limiter. Usually you can't get above 3K RPM.

How old is the battery?

I don't think you needed to replace the coils. Did you use the correct plugs? What were they?

Put the car in gear like 2nd or 3rd with the J-Shifter to hold it in that gear. Now take it to red line.

Lastly check again for codes.

Report back here with the results.
.
.
.

 

First I must say that was FUN!! LOL! I never had taken the car to the red line.

Anyhow. the battery is new, maybe 3 months old from Pep Boys. The spark plugs are Bosch brand Iridium, pre-gapped. I doubled checked the gap on each plug and they were good.

My cousin, who is a mechanic, let me know that I likely wasted money by replacing all the coils. I know two were bad so I thought I'd just replace them all, doh!

As for taking the car to the red line, it worked fine in 2 and in 3 all the way to the red line. Then I put it in D and hammered it. At 5500 rpms there was a big kick so I let off the gas. Car ran fine again, so I repeated in D and the car kicked again at 5500 rpms.

The car runs normal otherwise and the engine light has not returned.

Thanks for your help!!

 

None of those codes indicates an O2 sensor problem. I would check fuel trims and see if the car is going way lean as indicated by the P0171 and P0174 codes. They could be related to the MAFS going bad, but I would be sure by checking fuel trims. With that many misfire issues, the catalytic converters may be damaged and the exhaust is too plugged up to let the car rev freely. This is more shooting from the hip without a data stream readout, though.

 

Previous code did show the O2 sensor problem. I gambled and bought the before CAT sensors because I could not determine which one was bad. I was told to buy them in pairs by the local import repair shop. It seems to have helped but I am not sure if the repair shop was just trying to make more money off me to make my buy two sensors. I am wondering if the problem I am having now is because I need the after CAT sensors too?

What are fuel trims? Is that an easy question? Or can you show me where to look them up?

 

Well if it will go to redline in 2nd and 3rd it should be OK in drive? If you got to redline in 3rd then the I think the fuel system is putting out enough fuel.

It is a bit fun too! I still can't find the top end except that it does top out at 155 mph. Seems like there are more RPM's left in it too?

Can you give more detail on what happens at 5500 rpm? I am not sure what you mean. Does the car bog and stop accelerating? Any chance it could be the transmission shifting or doing something else?

That's why I suggested the tests in one gear. That eliminates shifting issues giving you problems.

No problem replacing the coils as it won't hurt anything but I need to ask. Factory coils or aftermarket? If aftermarket which ones did you use?

Have you checked codes after clearing them?
.
.
.

 

At 5500 rpms the car kicks almost like a backfire but the whole car feels a kick. Kind of scary when accelerating at 90 mph, eek! I was ready for it the second time. It did the same thing when I didn't put the air duct back on properly and tried to accelerate fast from 0 mph. It kicks hard and you can feel it throughout the whole car.

I bought the coils at Autozone. Duralast brand.

The engine light has not returned. Will codes show up without the engine light on?

 

Yes. Codes can be stored so it's worth a check.

Don't know why it happens at 5500 RPM but I don't think there is anything special about that RPM?

Has the transmission fluid level ever been checked?
Has the transmission fluid been changed?
.
.
.

 

The only thing about 5500 rpms is that it happened both times there. The transmission fluid was changed 6-9 months ago.

I'll check the codes to see if anything pops up. Thanks for your help!!

 

Maybe fuel trims, too, though by 5500 and WOT it's doing quite simple fuelling.

 

Just checked the codes again. All of them are in PENDING status:

P0175
P0300
P0301
P0304
P0307
P1316

This is much better than before as all 8 cylinders were misfiring along with several other codes.

Also, how do I check the fuel trims?

 

That's too many codes so let's clear them and see what comes back.

You may still be getting misfires at 5500 RPM but with you holding it in gear to redline that should have made it misfire too and it did not.

So it's a bit puzzling right now.
.
.
.

 

Will do. I'll drive it around a bit...

 

Weird. On an STR we don't really see:
P0175 = running rich
P030x = misfires, which look like lean
P1316 = misfires, ditto

 

It appears that I am eating a lot of gas. I am going to fill up tomorrow and average my mileage for verification.

 

Maybe running OL (see below), in which case something bad is happening and one or both cats are at risk - if they're even still working. I'd check it is running CL and then the fuel trims.

 

How much fuel you use does not help. Clear the codes then drive some more and post what codes come back.
.
.
.

 

Okay, cleared the codes and the engine light has returned with the following:

P1000 PENDING
P0128 (there were 2 instances of this code)

 

Well worth getting codes PDF / JTIS - both are free downloads.

P1000 turns to P1111 if all's well

P0128 is a coolant temp aka ECT sensor issue and needs fixing as it can't fuel properly so everything will be guessed!

 

Thanks!! I'm on it!!