I have had a hesitation problem on and off for a long time in MY06 car. After the car has been running for say 20-25 minutes there will be throttle lag/delay upon putting my foot down and the car accelrating. I almost feel to the point that my friends Type R is much quicker off the mark... untested theory however.

I am running a Spoon N1 dual exhaust with Mugen manifold and an AEM v2. I have 18" wheels which even though they are 18" aren't much heavier than stock wheels. There's a custom front grille on the car which is aluminium. It might be worth noting the holes for air flow into the radiator are smaller than a stock one. The manifold has a smallish 1cm deep dent where it connects into the rest of the exhaust/cat. I bought off a member on here and I don't think thats the problem as I've had it for a good 10K miles.

Obviously I understand it's going to be a process of elimination but anyone have any ideas?

The car has 28K and has always been serviced on time.

 

Its now running too lean.

 

Going to go through the FAQ/Tech stuff on here tomorrow anything else you would recommend?

 

Look for air leaks if you recently did any work and its a new problem.

 

It prob is running a bit lean, but that will make is faster

Check my Hesitation guide in the FAQ.

MAP / Lambda / Plugs are often the culprits.

If it's an air leak, you will have idle problems too.

 

It's fine on idle its literally just when I pull away or apply power to accel.

 

MAP would be my bet.

But do some checks as per the FAQ and see how you go.

 

I'd suggest O2 sensor, but not enough miles on the clock for that to start failing, unless you're v unlucky.

 

Disconnected the MAP sensor from the intake manifold. Gave it a good clean and a couple of taps. Touch wood the problem seems 90% sorted. There is still some slight delay/hesitation in higher gears. Pulling away, 1st, 2nd and 3rd seem much much better, gave the car a good 20 mile run to make sure aswell.

Will be having a look at filters, connections and the rest of the engine bay tomorrow.

 

Had very same problem and bought a new map sensor from hard top guy in the States while I was over there. Then after putting it on my car it would not idle properly and had a bigger flat spot! Posted on here and MB came up with the solution I had forgotten to put the rubber O ring that comes with the sensor on as the original was stuck to the bottom of the sensor and I never saw it.

O ring on now not drawing air in both the old and new problems solved! Hate to think what that would have cost at my dealer if they did not pick up on it as well thanks again MB.....