I keep having the same stupid problem during accelerations.
The car runs fine at WOT. But when I accelerate under part throtle it bogs down and losses power right at 3200-3300 RPM consistently, very annoying (NO SES codes)
I have cleaned MAF, TB and the new injen knockoff didnt affect the situation at all. I also reset the ECU but letting it sit for 24hr with battery unplugged.

I know some are tempted to say its my coils, but if that were the case I dont know why would it run fine at WOT. And get this, the other day I washed the engine and the problem went a way for a few hours, until it dried I guess....man, WTF???

 

Maybe it's the MAF going bad. Or maybe a fuel problem.

 

Replace the MAF before you burn it down.

 

Ok so I am taking everyones word and will order a new MAF, do I just get a stock MAF or are there better options? Do I need reset ECU again?

 

if your coil is bad, I bet your WOT run will be really crappy and worst than what you feel @ part throttle. your CEL will definitely go on and probably it will blink too due to misfire.

if your MAF's bad, dont expect to see the car goes to WOT at all.

I would check for intake leak after MAF sensor (i.e. the crank ventilation hose and VIAS tubing). seems like you are not getting enough fuel around that rpm range.

 

have you tried cleaning your fuel system?

 

I am with you there, I am going to look for leaks next and also change the in-tank fuel fliter/strainer to see if that makes a diff before getting a MAF. The car seems to be running fine at WOT, at least I think, doesnt hesitate or miss.
What bothers me is how it losses the power at a very specific RPM, almost as its being controlled by the ECM.......weird stuff, like if its retarding the timing or something, its very predictable.

 

why not take it to the dealer and just get it diagnosed? then you can fix it. i have been tellling ppl here to do that for the simple fact that you will change the MAF and the COILS and it still may not fix the prob. then you will really want to burn the *****..

 

I have thought of that but the dealer wont look at it with an injen intake, y-pipe, etc, etc. I would have to jank all that off and its a pain in @ss.....

 

you can check the fuel pressure to see if your fuel pump is working properly or the fuel filter is clogged. I wouldnt suggest to replace anything until the cause is determined.

your instinct about the ECM can be right. around 3000rpm, your car is operating under close loop operation. that means the ECM adjust fuel delivery thru MAF sensor and O2 sensor. So if the O2 sensor is broken and send the wrong signal to the ECM, your ECM will correct the fuel delivery per what O2 sensor monitored. When you floor the pedal to the metal, the car is in open loop operation, that means the car only depends on MAF sensor to determine how much fuel you will need.

this is little test you can do: when the engine is cold, run the car in partial throttle around that rpm range to see if seem symptom is observed. because the ECM puts the car in open-loop operation when the car is cold in order to protect the engine internals. If the problem is still there, then the cause may be something else.

hope I am not confusing you.

good luck~

 

$20 it's a coil. My 96 experienced a similiar problem under light load and it turned out to be a bad coil that was barely out of spec according to my volt-meter. At WOT the car was fine. Also, if you have an underhood intake and the temps are warming up where you are, you could be experiencing the all too common hot weather bog that occurs in the mid 3000rpm range. This bog/stumble occurs because the MAF and temp sensor have trouble dealing with the hot turbulent air.

How long have you owned this car?


Dave

 

It is quite strange that your car experiences these problems in the same RPM range, but I would argee with Dave B that it is most likely a coil problem (but not bad enough to trip a code). It's better to replace them anyway since they have known problems as it is...

 

whan i had coil probs, i only felt it when i floored her..when normal driving, i couldn't feel any probs..

 

Thanks Dave, I have the injen knockoff intake, but it does it when the engine (and outside environment) are fairly cool, also did it with the stock intake.

I am going to check the coils with voltmeter per my haynes manual and also try out what [maxi-overdose] suggested....will report back

Thanks for the help all!

 

So I decided to take out the MAF and clean it with CRC Elektra-Kleen....when I took the sensor out it was pretty dusty in and around the sensor wire so I sprayed at will thouroughly. Put the sensor back, reconnected bat (to reset ECU), and took car for a ride and.....

HOLY ****!!!! like driving a new car!!! all the bog down is GONE and the motor just screams thru all the RPM's and I can even hear the VIAS kick in after 5k rpm....I am shocked, the car runs and pulls like a dream now, cant believe what a diff this has made!

So like the Ford commercial says, If you havent taken a look at your MAF lately....Look again!!!!

Thanks for all those that helped....I was growing frustrated with the car lately but I love the Max now!!!

 

You said you cleaned your MAF before. Not thorough enough or something?

 

No, I confused the MAF for the air temp sensor before !!

 

Kiosk how many miles are on your car? mines got 40,000 maybe I should clean mine but I get a little worried when playing around with that stuff.

 

My car has 108,000 miles, so a cleaning was prbly much needed. I used the electric parts cleaner from CRC which dries almost immediately upon contact, my worry too was "wetting" the MAF which I heard kills them but this stuff took care of the job.