Air Flow Or Fuel Problem

[lexyman]

Hi all. My car has been in the garage for the last few days. When on the motorway i have been noticing a lack of performance. All of a sudden last weekend it seemed to go totally flat. It went to the garage and had a new air filter and apparently the fuel filter is in the tank. The ECU says all clear.

When i accelerate gently it is not too bad. As soon as i put my foot down hard whatever gear it feels really as though there is no fuel or air. Tick over seems fine. Any ideas? I think it is air intake related what sensors are there?

[Gord]

Could be one of the cats broken up, stopping the gas getting out :o

[lexyman]

Could be one of the cats broken up, stopping the gas getting out :o

Thanks for that he did say he checked but i will get him to re check. How many are there? could it be an air flow meter?

[Rob]

no air meter on the IS only a manifold pressure sensor

[lexyman]

no air meter on the IS only a manifold pressure sensor

Hi thanks for your input. Can you confirm that if the manifold sensor was faulty that it would show up in the ECU with an error code? If that is the case then it sounds like it must be the CAT as there is no error in the ECU - thanks again.

[kritzresn]

Checked the sparks as well ?

[w77]

How does the manifold pressure sensor look like? Had the same problem with my previous Merc and it was the air sensor.

[Rob]

the map sensor is just a black block and it located on the rear of the engine block - u can just about see it.

if it is not working u will get a fault code.

[Gord]

no air meter on the IS only a manifold pressure sensor

Hi thanks for your input. Can you confirm that if the manifold sensor was faulty that it would show up in the ECU with an error code? If that is the case then it sounds like it must be the CAT as there is no error in the ECU - thanks again.

Yes it would show error code if sensor was not working.

3 cats in total, 1 main under the car, 2 pre-cats in the manifold, it was one of the pre-cats that went on mine, at times when running the car (when i didn't know what was wrong) it would sort of be missing, hard to rev, at 1st i thought it was a spark plug.