My 04 disco, which I had for about 2 weeks now developed major hesitation, when I take my foot of the accelerator at highway speed. Gi ing gas there is no hesitation only when I let the gas pedal go. Sofar I have done the induction cleaning, engine flush with gunk, power steering fluid flash and I have been on the second tank of premium 93 octan gas. The indu tion was done around 50-75 miles ago. The PSP still needs to be replaced but it didn't arrive yet.any idea what might be causing the hesitatiin?

 

Clean the throttle body with a cleaner rated for that, and consider cleaning the MAF. One brand is CRC. You want to do this when parts are stone cold, should not be much of a problem these days. Also clean the IACV and the hole you remove it from.

 

Thanks for the reply. I did clean the throttle body very thoroughly, which was btw very dirty. I'll have to look at the rav's manual to see what and where are Maf and iacv.

 

Great idea. Near where you have been working , but not past the air filter. Good idea to look in the shop manual, under engine management.

 

I know now where MAF and IACV are located, Rav's manual says to discard the O-ring and fit new O-ring, obviously I don't have a new O-ring, is this necessory? and when I was cleaning the throttle body, I had to releas the ducts and only thing that I saw, where the MAF is, was a plastic mesh. So how do I clean this, I don't want to damage anything and how do I clean IACV.
I just paid around $20 for only 5 O-rings for power steering pump and gear box (couldn't believe it but no way around it, since some of the O-ring's were not available any where else). I wish I knew about the MAF O-ring, the dealer is > 20 miles away.

 

You do not need a new MAF o-ring, unless yours is damaged, and then you can buy a universal one, its just a rubber ring.

Now when you say there is a hesitation when letting off the gas what exactly do you mean?

 

When I let the gas pedal go, it feels as if the engine is stoping and restarting, like a sudden downshift.
It feels like when you push a manual car to start it, car is in first gear, your foot on the clutch, when you have some speed you let the clutch go and the car hesitates and than starts.
Now in my case this happens, when I let the gas pedal, especially when I first take my foot off it or even want to slow down. No hesitation what so ever, when I give gas. My brother is also some what mechanically inclined and he said that I might have vacuum/air leak, that when the throttle is closed, the fuel and air mixture mix is not the right one. When i did the induction, I had to take off the vacuum line, which was fitting very thight and now it is not as tight, but I don't think it is so loose that it is causing a leak. I saw on YouTube how to clean the MAF and IACV, basically just spray it with carborator cleaner, I hope this is right?

 

Do you have any fault codes? Stay away from the MAF, if you had no codes and you cleaned it odds are 50/50 you have killed the MAF.
Send me your number and I'll call you.

 

I did not clean the MAF, just the throttle body as described in the induction cleaning. I will get a code reader, to see what the codes are.

 

Just some backround first.
Check engine light first came on after power washing the engine to check for leaks, it went away by itself after around a day. The Service engine soon light came on again after induction and cleaning the throttle body, it did not go away this time. I had to power wash the underside and also the engine compartment one more time and after this was done the check engine light was flashing for few minutes and than it stayed on. Today it turned of but than it came back.
I got the code reader and got 11 codes in this order
P1300, P0308, P1129, P0300, P0301, P0302, P0304, P0303, P1412, P1415 and P0152. I cleared all codes and turned off the engine light.
Could all of these be related to power wash or is there something else wrong?
Thanks