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1993 gmc sonoma 4wd help please


julie22_20
07-01-2007, 08:48 AM
I have a gmc sonoma and am getting a code 33 (map sensor) I replaced the map sensor, as well as the knock sensor connector as the wire touched the manifold and burnt.

I am still getting the code, it says it can also be caused be unstable idle, or engine mis fire.

two weeks ago I replaced the egr valve, and spark plugs & rotor.

I started getting the code after I had a new catalatic convertor and muffler put on.

Any ideas??:banghead:

julie22_20
07-01-2007, 08:51 AM
OH, i don't know if it will help but it is a

4.3L TBI engine code Z

MT-2500
07-01-2007, 09:27 AM
OH, i don't know if it will help but it is a

4.3L TBI engine code Z

Make sure the map sensor is getting good vacuum to it.
Check wiring and plug in.
If not remove TBI and check base gasket and vacuum ports in TBI base.

Check map voltage at idle and with engine off and post back voltage.
You should have 5 volts reference voltage and signal voltage should read around 1 volt at idle and around 4.5-5 volts engine off key on and should raise up with engine load.

Post back voltage readings.
MT

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