Recently my car started acting really weird. the car will idle at the normal 1400 and it just goes up and down from 1400 to 500. it act likes its going to die. when i hit the accel it blows out black smoke and its really rich.
85 2m6
- Thread starter rise474
- Start date
Did you check the EGR tube that goes from the exhaust crossover pipe to the bottom of the upper plenum? These are notorious for cracking at the seams. while idling spray some WD-40 around the flanges. If it stumbles worse, You need to replace the tube. Also the EGR valve can get carboned up and leak. You can remove it and clean the carbon off the ports and the valve. If you replace the tube, Get one for a 1988 Fiero. These were made using a flexible tube and do not crack as easily. You can get them at www.fierostore.com
Another spot overlooked for vacuum leaks is the plastic lines that the rubber hoses attach to that pass under the plenum. These can split length-wise and leak but look fine.
If you think it is a sensor problem, There 3 sensors that will drastically affect idle/running rich are the MAP (you already changed) the O2, and the IAC. Usually a bad sensor will set off the check engine light but not always.
Was there any work done on the engine recently? was the throttle body removed?
Another spot overlooked for vacuum leaks is the plastic lines that the rubber hoses attach to that pass under the plenum. These can split length-wise and leak but look fine.
If you think it is a sensor problem, There 3 sensors that will drastically affect idle/running rich are the MAP (you already changed) the O2, and the IAC. Usually a bad sensor will set off the check engine light but not always.
Was there any work done on the engine recently? was the throttle body removed?
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Reacently i have replaced all 3 of those sensors plus the intake manifold gaskets. My check engine light comes on right when i hit the pedal. Thats when it satrts acting weird. I took my intake manifold off a couple times recently and thats the only thing that would require my throttle body moving at all. i made sure the larger tube that comes off of it was connected still.