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Hi im new to the these forums, thought id give it a try, anyways i bought a 01 civic ex, i noticed not too long ago my engine light has come on and been nothing but problems latley. The car goes in limp mode in the morning about -30 degrees celcius, i had a map sensor code and i just replaced it but still shows up as p0108, so i shut off the car, cleared the codes and it limp mode was gone, however the car has lack of power and jolts back and forth in low rpms but no misfire codes.
Just now i get a code p1491 which i believe is for the egr valve.

I really dont know what to do anymore it seems like everytime i fix what the CEL is on for, more problems show up

 
Rep Power: 518

For P0108 the computer had to see MAP voltage at 4.50v or higher for at least 2 seconds. Having a scanner that can read engine data would be a huge help so you can see what the computer sees.

I'd be inspecting computer data and real time voltages to figure this out. Could be losing the ground for the MAP sensor. Could be other possibilities too, but I'd still expect an electrical issue of some sort on this.

Does the problem go away when it gets warmer?

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P1491 is EGR valve insufficient lift.
Valve did not open when the computer tried to operate it.
Could be frozen shut, could just be a bad EGR valve (or its position sensor, part of the valve).
I can't tell from here what your issue is, but bad EGR valves were common here.



HTH

 
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Well the issue i had when it was cold was limp mode and map sensor code, i shut the car off and cleared them and limp mode was gone but on my way to work the car was jerking back and forth, on my way home when the car was warmed up i got a cel and showed as a the egr valve code.

 
Rep Power: 518

IMO I'd worry about the MAP code, solve that first since that makes it run bad. You already fired a sensor at it and didn't fix it, so I guess it's gonna take some skills now.

Then take care of the EGR...unless you have an extra $150-200 to toss at it before taking care of the first problem.

 
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I cleared the code once again and now nothing comes up, but yet i still get a slow back and forth movement at highway speed and the odd bad jerk at low rpms