99 cougar BIG acceleration problem

[stratsmith]

Im a newbie at this board,
I bought this 99 in April of this year, and just recently the acceleration has dropped dramatically!!
2.5L manual 5spd., my acceleration band used to be from 3000 up to 5000 rpm.
now it wont even go over 70mph! Im being easily passed by minivans.
Each gear starts out really slow even with full throttle, and then when i get to 3100rpm in each gear it picks up a little.
Im getting a low coolant light but overfill reservoir is at max.
Seems like its starving for air, or fuel.
also, while idling, rpms dip below 800 or 900 rpms. and never used to do that.
Lots of engine noise too, my muffler is barely putting out anything
Not sure if thats enough info.
I appreciate any help!

[jakegday]

im not sure what it IS, however it COULD be something just as simple as a fuel filter, or an extremely clogged catylic converter, both very cheap considering the problem....

[beyondloadedSE]

I would check the main cat which I think is the problem. If its bad, the dealership will replace it for free since it comes with a 8 year/80K mile warranty.

You may also want to make sure your IMRC is working.

[stratsmith]

Ok, So after the two responses.. i decided to check out my exhaust..
Last night I loosened the flange just before the cat.. and noticed a world of difference...almost back to normal except for the noise.
Drive around the block.. and everythings better.. problem solved right?
No.
Then the next morning, i go about a half a block.. go to accelerate after a stop sign, i get maybe 100 feet and it just dies. belts are fine.. electrical still fine.
i turn the key and not even a click.
did driving around with a clogged cat kill my engine?
is there a fuse or something i can check?
fuel pump?

[jakegday]

im pretty sure theres no way a clogged cat, no matter how clogged, could destroy an engine, if it was your fuel pump your engine should still at least crank when you go to start it, im stumped

i thought i'd add that one time i had a car that would start sometimes and not start sometimes, and sometimes just die and wouldnt start for hours, sometimes days, turns out it was the fuel filter

[jakegday]

Originally Posted by beyondloadedSE

You may also want to make sure your IMRC is working.

whats IMRC???

[stratsmith]

i think i have it somewhat figured out...
I thought the electrics were fine but my gagues didnt light up when i turned the key.
i replaced the ignition/headlight switch fuse and everything came back on including the alarm!!
It started and drove for a half a block and the fuse blew again.
So its probably my alternator or battery.

[mikecox1]

Originally Posted by jakegday

whats IMRC???

the imrc motor is an emissions control device and nothing more mine was froze for two years and did nothing for the engines performince

[beyondloadedSE]

Originally Posted by mikecox1

the imrc motor is an emissions control device and nothing more mine was froze for two years and did nothing for the engines performince

brought up an old thread only to give the wrong answer.

IMRC = Intake Manifold Runner Control. It has nothing to with emmisions. You must be thinking of the EGR (Exhaust Gas Recirculation) which again really does nothing for performance standpoint other than increase gas mileage and lower intake temperatures to prevent detonation.

Just so you have a picture of what the IMRC is and what it does, its the silver box located on the front valve cover. Chances are you have a plastic cover over it that says 2.5L duratec. But if you were to remove it, this is what it look look like.

Picture of IMRC on Cougar/Contour duratec engine


The IMRC is controlled by the car's pcm and tells it when to operate. At wide open throttle the IMRC turns on and and pulls on the linkage to open the secondary butterflies at 3250 rpms. At less than WOT, it opens at 3750. These help give the car more low end torque to get the car moving. So what do these secondaries look like?

The secondaries are located in the lower intake manifold of the engine. As you can see the LIM (lower intake manifold) has primary and secondary ports. The secondaries are what have the butterfly valves and whats controlled by the IMRC.

LIM


Primary and Secondary port

[jakecovington]

i have the same exact car, and the same exact problem, did just the exhaust and the alternator fix it ?