Delayed acceleration
 

My girl friend has this 2000 Protege that recently started to have delayed acceleration, a safety problem when trying to get in the traffic quickly at an intersection, initiating a passing maneuver, etc. I noticed it while driving her car yesterday and she admitted to have noticed it since a month.

I was able to duplicate the faulty behavior after putting the car in "Parking" and activating the throttle cable from under the hood in quick successive pushes. The delay is about 1 sec.

Since the transmission is not involved, I was wondering if it could be the carburetor or something else and if there is any easy way to troubleshoot further before taking it to the doctor.

The car starts well and does not misfire at any RPM although I found it a bit sluggish when climbing hills. So, I ruled out spark plugs but I could be wrong, I am no expert.

Thanks for any suggestion

I'm about 99.9% certain that the Protege in question does not have a carburetor at all, so you can safely rule that one out. I'm thinking the first thing you should do is have the OBD-II codes read (dealership, repair shop, and even some auto parts stores can do it). As for the spark plugs, I'm thinking the chances of them being the issue is pretty darn close to zero.

Keep us posted.

OBD reading done
 

Thanks shipo!

So, I have got a Service Station to get the OBD read today. The device read 3 anomalies:

P0402 (Exhaust Gas Recirculation Flow; Excessive detected)
P0171 (Fuel Trim, Bank 1, System too Lean)
P1170 (H02S-11 circuit too high or low (bank 1 sensor 1))

The guy there told us that he would need to dig in to know exactly what's wrong, possibly a sensor according to him.

Not sure what the most rational way to go from there as these faults are pretty cryptic to me. Like is-it worth trying to clean the injector first with some commercial mixture to pour in the gas tank or would that be a waste of time and $?

Any suggestion welcome, thanks!

While some might disagree, I will also opine that Injector Cleaner has less than a 1% chance of doing anything positive. I too would lean to either a sensor (O2 sensor to be specific), or the EGR itself. I might also be inclined to have a look-see at the MAF sensor.

So, knowing what might be involved (sensors, etc.) we now have to decide whether this type of final diagnosis/repair is best done by the Mazda Dealership or if we can trust the corner service station with it. What would you do (assuming you don't do it yourself, because we can't)?

If you believe we can/should avoid the Mazda Dealership and its high hourly rate, what precaution should be take in dealing with the corner service station (questions to ask, use of second hand parts, etc.) before leaving the car with him?

Thanks again for your advices!

Last bit of info:

My gf noticed that when the gas tank is more than half-full, the problem is not as noticeable.

Could it be some pressure balancing problem between the gas tank and the injector? Combined with a dirty injector that become sluggish when too much vacuum is created in the head volume in a half empty gas tank?

:confused:

how can you just make the acceleration of the MP5 quicker? are there chips out there that u can buy for this upgrade?

Well, we don't want it quicker than normal. Right now, it's faulty, i.e. sluggish. We just want to figure out what has to be fixed, and if a trip to the dealership is necessary or if we can take the risk to take it somewhere else.

I had a problem that sounds similar on a Mustang. You would press the accelerator pedal and it would hesitate momentarily before accelerating. In my case it was a dirty throttle body. Get some throttle body cleaner from the parts store and clean it up. It should be pretty easy to take out. Spray it down real good and use an old tooth brush to get the gunk off.