I've got a 99 Tahoe, 112k, 5.7l 4wd suffering a very tough to diagnose (for me) loss of power for the last month or so. Forgive the long explanation, but I'm hoping someone else out there may have had a similar situation..
The issue started on long slight inclines as a shudder during climb w/ RPM's 1000-1500. Keeping the RPM's above 2k, seems to alleviate the shudder entirely. It got slightly worse over two weeks or so, ultimately resulting in a pretty significant loss of power when stomping the throttle. I pulled a PO306 (cyl6 misfire) from the service light and replaced all plugs and wires. That gave me almost all of the power back for a few days. Then during that same 1/2 mile slow climb, the shudder returned and engine light with it. A new fuel filter at this point. A few days later when trying to accelerate up a hwy on ramp, all power fell away. I pulled over and GENTLY worked the throttle to get me back home. Even conservative green light acceleration would result in nearly complete loss of power. Brought it to a shop, they tested the pressure at 45-55 psi and said the fuel pump was on it's way out. Those numbers seemed close to spec, but I replaced the pump anyhow (myself). Once new pump was in (yesterday), I took it out to test 0-60 on a flat, hard steep climbing, slow grinding climb, everything was totally good to go. Super responsive, etc. Seemed like the new pump fixed it. Then this morning.. on THAT SAME slow climb.. the shudder returned, engine light is back on again. I can feel the truck bogging down on nearly any incline again, and have to keep the rpm's up to avoid that shudder, loss of power. Aside from finding a way to work that doesn't include any hills...
- does anyone have any ideas? I'm thinking maybe it's bad compression... valve cover, fuel pressure regulator, something in that neighborhood??? Any suggestions are very appreciated!!
The issue started on long slight inclines as a shudder during climb w/ RPM's 1000-1500. Keeping the RPM's above 2k, seems to alleviate the shudder entirely. It got slightly worse over two weeks or so, ultimately resulting in a pretty significant loss of power when stomping the throttle. I pulled a PO306 (cyl6 misfire) from the service light and replaced all plugs and wires. That gave me almost all of the power back for a few days. Then during that same 1/2 mile slow climb, the shudder returned and engine light with it. A new fuel filter at this point. A few days later when trying to accelerate up a hwy on ramp, all power fell away. I pulled over and GENTLY worked the throttle to get me back home. Even conservative green light acceleration would result in nearly complete loss of power. Brought it to a shop, they tested the pressure at 45-55 psi and said the fuel pump was on it's way out. Those numbers seemed close to spec, but I replaced the pump anyhow (myself). Once new pump was in (yesterday), I took it out to test 0-60 on a flat, hard steep climbing, slow grinding climb, everything was totally good to go. Super responsive, etc. Seemed like the new pump fixed it. Then this morning.. on THAT SAME slow climb.. the shudder returned, engine light is back on again. I can feel the truck bogging down on nearly any incline again, and have to keep the rpm's up to avoid that shudder, loss of power. Aside from finding a way to work that doesn't include any hills...
- does anyone have any ideas? I'm thinking maybe it's bad compression... valve cover, fuel pressure regulator, something in that neighborhood??? Any suggestions are very appreciated!!
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