Just purchased 2003 merc gm

Reduced engine power on GM vehicles has to do with the electronic throttle control .( Electronics ) Your best bet is to take your vehicle to a qualified repair shop or a GM dealer ! GM Reduced Engine Power Mystery Solved 04 Silverado REDUCED ENGINE POWER Case Study Part 1

the Reduce light, is not transmission , light correct?

what country are you in., ( asked 10000 times zero answers .well 3)
what engine,? we cant guess engines, here, and it seems to be just that, the engine issues.??? felt is real;. sure..

is the tranny stick or auto...... autos can slip and go to limp home mode just like engines do. so what transmission?

if in USA all scan tool made will scan an ISUZU. 1996+
so then you see DTC errors. and why its in limphome mode.
"your reduced power deal"
there is no other way,,,, besides, 1000 pages i type on how to test EFI with not scan tools.....I can do it. but refuse. to type that here..
as one famous poster said.
you want 50 years experience on 1 fixya page. :LOL

i wont say that, I say.
1: check all fuses.
2: make sure battery, voltage is 13.3 to 15v running, if not you have charge system failures, fix that first because EFI will not run on dead batteries, ever. (discharged for any reasons)
3:Scan it. do so and tell the DTC errors, im sure you have them.
4: or did you skip the 60,000 mile major tuneup, or never did one this decade,,,, wow, that be why , huh?

Do not need codes to have problems

There could be codes, but only Enhanced Codes,
that a Generic Code Reader can not get

That is why I consider a free code read at parts
store a waste of time

If you own one fine,your using the internet,learning
as you go & trying to do your own work,that is okey

But the real data you need,is on a scan tool & doing
a road test with it

Only professional tools will allow you to
look at the required data, to hopefully find
a problem or several

Many things can cause a cylinder misfire

Almost sounds like maybe a motor mount issue.

More than likely you have a misfire due to a coil. In 11 years of working at a ford dealer as a driveabilty specialist I have never seen a crown vic injector fail. If it has a misfire code again I would replace the coil and plug on the appropriate cylinder.

hi, unfortunately this is one of them how longs a piece of string things, you could purchase a code reader reset the error code but, what you have to think of is what caused it to do it in the first place, accelerating to hard should not cause an error ( i do it all the time in my car lol ) but it might be related to the 02 sensor getting to much unburnt fuel passing it which would cause the engine light to come on, though if the car is running as normal i doubt that will be the issue, i would myself on a car like that take it to the main dealer and get them to check it out, as buying an inexpensive code reader might not cut the mustard with this one, and parts being as dear as they are for merc's i would play on the safe side, spend a few bucks to save a load...sorry not much help

why do you want to do this. If the light is on, fix the problem ASAP.

lckydog18
I have a similar symptom. No engine light lite. It can be felt as I accelerate moderately from a standing stop. Then as my engine begins a climb in rpm in seems to hesitate for a brief moment and then continue to increase rpm. Not sure what this is.

Is this the symptom you were identifying?
Ed

Does it idle fine? Sounds like a vacuum leak.

Whne I worked at Ford , they had problems with the accelerator pedat electronic switch. The pedal is not connected to the engine with a cable, but with an electrical connection. You would have to have a scanner put on your vehicles computer and check for any trouble codes. Also give the Ford dealer your VIN # and they can check for recalls for that problem.