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1989 Chevy Corsica, Low fuel pressure or bad sensor?

1989 Chevy Corsica has lower than spec fuel pressure, but exhibits no problems under heavy acceleration at highway speeds (passing), so I’m not sure it’s a problem (yet). When cold, seems fine. As warms up, starts to surge somewhat when driving around 30MPH and idles rough and stumbles when starting from a dead stop. No blink codes (except code 12) and no check engine light. I suspect a sensor, but which one(s)?

If the fuel pump is lower than specs then you should replace the fuel pump. You may have a bad sensor but you have to get the proper fuel pressure to the engine first.

Thanks missileman. I’m inclined to agree except that it performs so well under extremely heavy load. If the fuel pressure was really too low for acceptable operation, it should falter then instead of actually improving. I’m trying to get my ex’s car back on the road for as little investment as possible, and I’m getting the sinking feeling that if I replace the pump it’s still going to have the exact same problem. And that job is no fun, so I’d rather wait until it is well and truely needed (which could be next week). If I could identify a likely sensor to replace (remember it seems much better when cold, so it appears that the problem starts when entering closed loop), I’d prefer to try that first.