Well since few days my car was bogging at random times. Did almost everything but later when i restricted the pipe going to tank after Fuel Pressure Regulator the car seemed to work fine and is working great till that (added the clamp to restrict fuel flow). This was a temporary solution just to find the problem.

Fuel pressure readings were

At Idle (750) 29 PSi

With Vacum Hose removed from FPR (WOT Condition) 40 PSi

Some dude says that this is normal ratings but I suppose the pressure should always stay 40+ psi no matter what idle or WOT.

What do you say is ideal Fuel Pressure for Idle and WOT?

Engine is 1.8 liter F18B similar design as F22B

 

Idle with the hose disconnected = 38-46psi
Idle with hose connected = 30-37psi

So at WOT did you notice if you had any vacuum? 40psi is between 38-46psi range with no vacuum. It is a bit on the low side of the range. That's where your actual vacuum/MAP reading would come in handy.

 

That shows that the fuel pump has no problem creating the pressure, and there is no restriction from the filter or to the rail.

Most likely the FPR is going bad.

When the vacuum hose is disconnected from the FPR it will see no vacuum. At WOT the same effect should happen, no vacuum at the FPR, thus the testing as provided by Ghost would mimic WOT testing without having to go to WOT.

If the pressure was raised by regulating the pressure manually and the car ran better it appears the FPR is no longer restricting fuel flow properly.

 

@GhostAccord at idle I am getting 1.2 volts from MAP and 17.2 KPa of Vaccum.

Here is my scan stats at idle without restrictions.


@MAD_MIKE some one said to me you are restricting and car would run rich so i pulled out spark plugs..... they were light brown. Some even did not had any color they ere orignal sort of colored

 

Normally if the FPR was working correctly, and you added further restriction to the return line, then yes. Clamping the return line would cause a rich condition by artificially raising the fuel pressure above normal specifications. But since the FPR is not restricting flow, which creates pressure in the system, the fuel is not going to spray out of the injectors correctly in the right amount.

Typically spark plugs should be a 'cocoa brown'(like the spark plug has cocoa powder on it) color to them when the air/fuel ratio is optimum. Not wet/black/darkbrown as that is running rich, and not white/bare porcelain as that is running lean.
Note #14


This image does not show as many variants of 'good/normal' plugs, but you get the idea. Not wet/black/sooty/clean/etc a nice light brown coating is about where you want to be.


To properly check spark plugs you really need a lit magnifying glass as a ring forms on the outside of the center electrodes porcelin insulator when proper combustion happens. If you have good eyesight you may be able to see the ring.

 

Love you man........ thanks for great information.........