Hey I'm new. I've been searching around but can't find an answer on this.
I have an 05 14X,xxx miles on it.
I think my PCM is bad and I dont know how to test it.
Its been giving me problems for almost two years now and I can't figure it out. I haven't been driving it much at all since I started noticing it wasn't acting right, but now I want to get her ship shape again.
Not throwing any codes so my mechanic (independent guy) wasn't too interested in digging.
I had an intermittent rough idle, some delayed shifting into second sometimes, and what I thought was atrocious mileage.
I replaced my coil packs, new delco plugs, air filter and it seems to run better in general, but there's still one big issue.
I came to notice (again after not driving more than a couple of miles at a time it for quite some time until recently) that when I filled up, the fuel gauge would not read entirely full. Then within 20 miles it would rapidly drop to 3/4 and then seem to drop at a normal rate with driving.
I thought it must be the sending unit.
I dropped the tank and replaced the whole pump with a delphi. The tank had about 5 gallons left in it at this time when the gauge had been reading empty.
I thought I was right and it was definitely the sending unit.
Tank went back on, went and filled it up, gauge read completely full.
I then drove about 40 miles then filled up again to get a mileage calculation, which looked great to me (at that point it took 1.4x gallons to fill it back up, allowing the pump to tell me it was done) The gauge seemed to behave normally during that drive (it never rapidly fell toward that 3/4 mark and said I'd gone from a tick above full to a tick under)
After refill the gauge went back up to above full.
Drove 30 miles and was at 3/4 of a tank again.
Kept driving and I'm now reading out 115 miles on half a tank - as if the gauge is just not factoring in that first quarter tank.
So I think its not a second bad sending unit having the exact same issue. Its either the gauge itself (which doesn't seem right)
Thoughts or ideas on how to proceed?
I have an 05 14X,xxx miles on it.
I think my PCM is bad and I dont know how to test it.
Its been giving me problems for almost two years now and I can't figure it out. I haven't been driving it much at all since I started noticing it wasn't acting right, but now I want to get her ship shape again.
Not throwing any codes so my mechanic (independent guy) wasn't too interested in digging.
I had an intermittent rough idle, some delayed shifting into second sometimes, and what I thought was atrocious mileage.
I replaced my coil packs, new delco plugs, air filter and it seems to run better in general, but there's still one big issue.
I came to notice (again after not driving more than a couple of miles at a time it for quite some time until recently) that when I filled up, the fuel gauge would not read entirely full. Then within 20 miles it would rapidly drop to 3/4 and then seem to drop at a normal rate with driving.
I thought it must be the sending unit.
I dropped the tank and replaced the whole pump with a delphi. The tank had about 5 gallons left in it at this time when the gauge had been reading empty.
I thought I was right and it was definitely the sending unit.
Tank went back on, went and filled it up, gauge read completely full.
I then drove about 40 miles then filled up again to get a mileage calculation, which looked great to me (at that point it took 1.4x gallons to fill it back up, allowing the pump to tell me it was done) The gauge seemed to behave normally during that drive (it never rapidly fell toward that 3/4 mark and said I'd gone from a tick above full to a tick under)
After refill the gauge went back up to above full.
Drove 30 miles and was at 3/4 of a tank again.
Kept driving and I'm now reading out 115 miles on half a tank - as if the gauge is just not factoring in that first quarter tank.
So I think its not a second bad sending unit having the exact same issue. Its either the gauge itself (which doesn't seem right)
Thoughts or ideas on how to proceed?