hello. 2003 monte carlo ss 100,000 km. losing power the most noticable between 60 km & 80km. replaced the air cleaner. no diff. have looked over the posts & seems the catillytic converter seems to be in the running. was going to tuner her up anyway, does that sometimes have something to do with the power loss?the engine light was coming on periodically before, however, now itstays on & i have smelt therotten eggs (very little)? any suggestions would be helpful as the hubby could dosome troubleshooting for me.

thanks

thanks

 

first of all you want to have the computer scanned to see what the code is.. overfueling could be damaging the cat and ruining the internals.. though it is possible that it is just the cat going bad and clogging... fuel pressure tests might need to be involved to test for bad regulator or leaking injectors.. really hard to say what else without scanning. .. possible misfire ?

 

just to add to what 1977 monte has said.

yes a CAt. Converter could cause a los sof power , With this siad remeber mos tof the time they do nto just go bad with out another cause of some kind.
So if you just replace it with out finding out why it went bad it will only be temopray fix at best.
btu the monte carlos have had this issue in the past also. So i would think it is worth the tiem to have it scanned to find out what the codes are it is putting out.

 

thank you both. will ge t the code & hopefully i can ge t some help then.

b ye

 

I'm guessing it's an EGR problem and it's probably sticking open a pit causing too much exhuast to be let back into the intake causing the rotten egg smell. Had the same problem on my 92 silverado. That's probably why you don't have that much power too is because there is too much exhaust going back into the system...stupid emissions.

 

I would be willing to quess that the O2 Sensor is causing this.
Pull the codes would be the first step.
Fuel pressure will not set a code.
Normally rotten egg smell is caused by an O2 issue or it needs a very good tune up....
As for a clogged cat. you should be able to tell by three ways.
One: the sound of the exhuast will change
Two: check and see (ok feel) how much exhuast is coming out of the tail pipe. Normally if you can feel something the cat is not clogged.
Three: Check the cat itself. If it is glowing a bright red. that means it is clogged.