MM drives sluggish please help!

[silversnake]

Car is having issues. Driving to my friends house one day my gas and brake pedel felt hard to depress as I let of the gas the car felt as if the calipers were sticking because the car slowed quicker than normal. No codes, took the car to get looked at and ran thru a scanner no codes or pending codes for trans and engine. My steering also feels rough. Feels like my engine is working hard to pick up speed. The strange thing about this is that it doesn't always drive rough. For example when I'm at a red light when the car is idleing on drive it has a slight shudder then as I accelerate it drives rough then smooths out and everything is back to normal. Somedays it drives fine but other days like crap. Please help.

[Mebot]

how many miles? have you done a tune up?... not sure about the calipers sticking but the shudder & sluggish response sounds like it may be your COPS and/or your spark plugs

Sent from my handheld Zack Morris iShoe 4S.

[RacerX]

I find it really odd that the gas pedal and brake would be hard to press on. Manually see if the throttle opens up easily. Maybe cruise control cable sticking? Vacuum leak???

[silversnake]

Car now has 86,xxx miles on it. I bought the car at 80,xxx miles. A week later I replaced the spark plugs, and change the trans fliud. Seafoam treatment the car was running beautifully until one day started misfiring. After running a love datalog I found cylinder 2 misfiring. I replaced the COP and everything was ack to normal up until last week. The throttle opens easily. Yesterday my adjustable pedal motor stop working and now only clicks when I press the button. My brake pedal sometimes doesn't depress when I start the car with my foot on it. I sprayed brake cleaner fluid around the intake manifold and vacuum hoses because I was told by an ASE certified tech to check for a vacuum leak. Sometime while I'm driving I hear a buzzing noise coming from what's sounds like the front Dri. Wheel. When it drives rough.. For some reason launches much quicker spinning the tires n midrange launches hard n fast but there is still a rough ride. Crazy I know. I love the car but not the issues I'm having because there is no codes to pull so I'm left with chasing the problem. Engine sounds louder than normal when it acts up n feels like its struggling for the rpm over 3k

[silversnake]

The car doesn't always drive rough though and that's what's bothering me. For example 10min out of a 30min drive the car drives perfect. Sorry for the typos ^^ in previous post spell check

[1 Bad Merc]

I would check the wiring harness for chafing. The MM's had some wiring in the engine compartment that would get chafed and cause all kinds of problems.

[silversnake]

I would check the wiring harness for chafing. The MM's had some wiring in the engine compartment that would get chafed and cause all kinds of problems.

Is it safe to unplug all the engine compartment harnesses then reconnect them?

[justbob]

Hard pedal, running rough, perhaps a vacuum leak inside the brake booster itself.


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[Rockettman]

^^^ I was thinking that too. Look into that booster.

[silversnake]

Ok today I was making a U-turn when suddenly my car cuts off. When I restarted the car
The steering wheel felt much looser and quiet when i turned the wheels far right and left ,drove normal but what I noticed was at a stop light I revved the engine and saw my battery light come on then off.

[silversnake]

Having my trans. Checked out tommorrow. Mysterious clunking noise at low speeds when I step on the gas.

[a_d_a_m]

First thing coming to mind is, as others said, a vacuum leak. But it sounds like you have a bunch of different gremlins that are not isolated to one problem.

[MMBLUE]

Check rear wheel bearings. Could be locking up causing stress. I just went through this.:cool:

[fastblackmerc]

Having my trans. Checked out tommorrow. Mysterious clunking noise at low speeds when I step on the gas.

Sounds like bad u-joint(s)......

[fastblackmerc]

Is it safe to unplug all the engine compartment harnesses then reconnect them?

Check the harness that runs behind the drivers side head. It may be rubbing on a bolt.

[silversnake]

Ill know today if its trans. to rear end related. I should know at 5pm est. ill keep you guys posted

[silversnake]

Check the harness that runs behind the drivers side head. It may be rubbing on a bolt.

Ill certainly take a look today

[silversnake]

He wasn't able to squeeze me into his busy schedule to test drive and examine my trans. An rear end. Prefer me to leave the car early. All free of charge. So I told him Friday will be the day I leave it, but meanwhile I'm goin to be checking for loose connections and vacuum leaks

[silversnake]

Can overrunning alternator pulley cause drivability issues when seized?

[silversnake]

Today I replaced my alternator overrunning pulley, serpentine belt, also reset the ecu. Car is running a lot better. Waiting until factory parameters settle to give my final assessment. I believe by the clutch pulley seizing may have causing stress on the engine.

[silversnake]

Does anyone have a diagram for the vaccum lines?

[RF Overlord]

Can overrunning alternator pulley cause drivability issues when seized?


I believe by the clutch pulley seizing may have causing stress on the engine.Doubtful. The only thing the one-way clutch does is allow the belt to slow down with the engine when the throttle is closed rapidly at high RPM. This is to reduce belt squeal and wear. Unless your alternator bearings were seized...then you'd tear the belt up before it had any impact on making your motor "sluggish".

[Mr. Man]

Doubtful. The only thing the one-way clutch does is allow the belt to slow down with the engine when the throttle is closed rapidly at high RPM. This is to reduce belt squeal and wear. Unless your alternator bearings were seized...then you'd tear the belt up before it had any impact on making your motor "sluggish".
Doesn't the clutch allow the alternator to be left out or turned off, skipped, however you phrase it, on WOT runs?

I read on here that a shudder on take off could be transmission fluid that needs replacing.

[RF Overlord]

Doesn't the clutch allow the alternator to be left out or turned off, skipped, however you phrase it, on WOT runs?No, all the clutch does is as I described. Turning the alternator field off at WOT is done by the PCM.

[Mr. Man]

No, all the clutch does is as I described. Turning the alternator field off at WOT is done by the PCM.
Gotcha.....:beer:

[fastblackmerc]

Does anyone have a diagram for the vaccum lines?

None in the shop manual. I believe there is one under the hood on a decal.

[silversnake]

None in the shop manual. I believe there is one under the hood on a decal.

I sprayed all vacuum lines with carb cleaner front and end no idle change. I also sprayed around manifold.... nothing

[silversnake]

I was experiencing sticky throttle for a month which was caused by me spraying the carb cleaner into the ports where the Tb butterflies link together. Sprayed the thing again today and noticed it got worse. After wiping the TB with WD-40 all is well