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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: 1979C20 on September 21, 2012, 04:26:50 pm

Title: Truck "chugging"
Post by: 1979C20 on September 21, 2012, 04:26:50 pm

On my 89 burb, a few nights ago the exhaust started "chugging" at a certain speed. Ot sounds like its missfiring. Then, after running like that for a bit the check engine light comes on with.code 44. Which is lean exhaust. So, besides fuel filter what could be possible causes?

Title: Re: Truck "chugging"
Post by: bd on September 22, 2012, 01:05:06 am

* a grounded O₂ sensor signal wire
* an open in the O₂ sensor ground
* a faulty O₂ sensor
* low fuel pressure
* water in the fuel
* (if used) AIR injection system pumping air into the exhaust system in 'closed' loop
* an exhaust leak
* MAP sensor slightly out of range
* faulty ECM