Please helpme!!!!!

[hawkgs]

Hi, my english is not so good, i'll try to explain my problem...

Maxima 2000, 124000 Milleage
i have very poor mpg (13-14 mpg freeway and city), mi car shakes a lot (feel like tugs when i'm driving). there's no SES light, but A OBDII scanner read the code P0720, so, i changed the Speed Sensor,i changed a used but in good condiitions set of coils, i made a full service (iridium sparks, filters, inyectors cleaned, motor oil) and nothing happens, the car still feels a lot of tugs and i'm desesperated. any help'll be apreciated, thangs and sorry for my english... i live in Mexicali, Mexico...


thanks....

[Nahkapohjola]

Originally Posted by hawkgs

...iridium sparks, filters, inyectors cleaned, motor oil)....

...also fuel filter?

Fuel pressure, MAF Mass AirFlow, TPS Throttle Pos sensor and Heated O2 sensors may be individually tested and verified up to a point. First check charge voltage and correct if necessary [bad alt = voltage spikes can be found out if alt cables are disconnected for tsting].

Bad Knock Sensor retards ignition, my ECU did not report that. Causes universal pwr loss [no hesitation].

MAF and TPS can also be cleaned instead/before replacement. Some links on page http://www.cardomain.com/ride/748507/9 ...also see 'Favorite Links'; theres 'some' reading...

My Spanish is worse than your english ...how's your Finnish?

.

[hawkgs]

Originally Posted by Nahkapohjola

...also fuel filter?

Fuel pressure, MAF Mass AirFlow, TPS Throttle Pos sensor and Heated O2 sensors may be individually tested and verified up to a point. First check charge voltage and correct if necessary [bad alt = voltage spikes can be found out if alt cables are disconnected for tsting].

Bad Knock Sensor retards ignition, my ECU did not report that. Causes universal pwr loss [no hesitation].

MAF and TPS can also be cleaned instead/before replacement. Some links on page http://www.cardomain.com/ride/748507/9 ...also see 'Favorite Links'; theres 'some' reading...

My Spanish is worse than your english ...how's your Finnish?

.

thanks for the reply, i think ther is no fuel filter in this model, but i cleaned the filter in the gas pump inside the tank. i'll check the TPS and MAF sensors, thanks...

[Nahkapohjola]

Originally Posted by hawkgs

...i think ther is no fuel filter in this model, ...

...but youre right! No filter mentioned in the FSM. Still theres the vacuum controlled regulator which may become faulty.

Pressure, see FSM page EC-55:

At idling:
With vacuum hose connected
Approximately 235 kPa (2.4 kg/cm2, 34 psi)
With vacuum hose disconnected
Approximately 294 kPa (3.0 kg/cm2, 43 psi)

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