Rough run, EVAP code, Related?
#1
11-13-2012, 11:47 AM
Rough run, EVAP code, Related?
Bit of background.
Bought my 98 blazer 4Door 4WD LS from a friend that blew the head gasket on it for 350 bucks. Chassis is clean of rust, but it was hit in the passenger rear end (drunk in a parking lot). Vehicle now has 175k on it, and I have done quite an extensive amount of work on it as it was very poorly maintained.
Spent a while rebuilding this vehicle since I had the time and a second vehicle while doing it.
Work I did last year:
Rebuilt heads by a reputable local shop
Head gasket set (Fel-pro highest quality gasket set)
Timing chain
Oil Pan gasket
Oil lines to oil filter and to radiator
Complete coolant system except heater core (Flushed clean)
Plugs, wires, cap, rotor
Tires
A/C Lines
Battery
Rear brakes (calipers, pads, and rotors)
I am sure I am forgetting more
Done this year:
Injector (Upgraded to the MFI Setup)
A/C Compressor
Misc Suspension (Front ball joints, sway bar end links Etc.)
Transmission/torque converter replaced with 87k Used model.
Front pads and rotors
Problem I am having is that each thing I replace has fixed one or more problems, and I am at this point I am still getting the following codes (no access to a tech2)
P0442 Evap Leak Small
P0300 Random Misfire
Also the vehicle gets poor fuel milage (15.4 MPG 80% highway driving), and surges when cruise control is engaged on highway (intermittently will jump from 1900 rpm to 2300 rpm at 65MPH, independent of load).
Wondering if this EVAP leak would cause the misfire and the funny driving on the highway? Or do I have two unrelated problems?
I have observed in my cheapo scan tool that the long term fuel trim is constantly changing, which tells me poor readings, but the o2 sensors are properly operating back and forth as though the engine is properly going lean to rich often.
As far as quality of work, I have taken and passed all of my ASE tests after going through a school program, but have never worked in a shop, so I am not certified. This blazer has been an adventure, but would really like to get it running better before the winter sets in. Just looking for anything I might have overlooked, or that is a common problem on these vehicles that I have not payed attention to
Bought my 98 blazer 4Door 4WD LS from a friend that blew the head gasket on it for 350 bucks. Chassis is clean of rust, but it was hit in the passenger rear end (drunk in a parking lot). Vehicle now has 175k on it, and I have done quite an extensive amount of work on it as it was very poorly maintained.
Spent a while rebuilding this vehicle since I had the time and a second vehicle while doing it.
Work I did last year:
Rebuilt heads by a reputable local shop
Head gasket set (Fel-pro highest quality gasket set)
Timing chain
Oil Pan gasket
Oil lines to oil filter and to radiator
Complete coolant system except heater core (Flushed clean)
Plugs, wires, cap, rotor
Tires
A/C Lines
Battery
Rear brakes (calipers, pads, and rotors)
I am sure I am forgetting more
Done this year:
Injector (Upgraded to the MFI Setup)
A/C Compressor
Misc Suspension (Front ball joints, sway bar end links Etc.)
Transmission/torque converter replaced with 87k Used model.
Front pads and rotors
Problem I am having is that each thing I replace has fixed one or more problems, and I am at this point I am still getting the following codes (no access to a tech2)
P0442 Evap Leak Small
P0300 Random Misfire
Also the vehicle gets poor fuel milage (15.4 MPG 80% highway driving), and surges when cruise control is engaged on highway (intermittently will jump from 1900 rpm to 2300 rpm at 65MPH, independent of load).
Wondering if this EVAP leak would cause the misfire and the funny driving on the highway? Or do I have two unrelated problems?
I have observed in my cheapo scan tool that the long term fuel trim is constantly changing, which tells me poor readings, but the o2 sensors are properly operating back and forth as though the engine is properly going lean to rich often.
As far as quality of work, I have taken and passed all of my ASE tests after going through a school program, but have never worked in a shop, so I am not certified. This blazer has been an adventure, but would really like to get it running better before the winter sets in. Just looking for anything I might have overlooked, or that is a common problem on these vehicles that I have not payed attention to
Last edited by Dr. Pepper PhD.; 11-13-2012 at 11:55 AM. Reason: Forgot year and model
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