Buick lesabre 94 idles but no power

Hello AF,

My Buick starts and runs fine, but stumbles, not backfire, as rpm's are increased and has no power or driveability. Symptoms began suddenly, ran fine nite before, began next morn. Checked fuel pressure at idle 37- 40psi, unplugged mass airflow sensor with no change. Thinking about CPS, ICM or Cam sensor. Any ideas on this would be greatly appreciated.

Did you have a recent tune up? Possible new plugs and/or wires in your future?

Does the check engine light come on? If you suspect sensors then a code may be thrown.

Maybe a cam lobe is wiped is not opening up a cylinder to the air. First rule = Check Compression- Is chasing your tail if you don't.

A Cam Lobe Eh?

I am not going to say that its not possible... But virtually unheard of in any 3.8 or 3800 from 86 on up...These are all equipped with roller lifters as well.. This is very far from common on any of the 3800's...

First, the fuel pressure with the FPR unplugged is LOW... This engine should fall into the 41-47 PSI Range with the Vac line connected, at idle you can be a few PSI below 41 Psi, but with the FPR unplugged you should be on the high side and a bit past it...

Also when was the last time the car was tuned up? Plugs wires and the like...

When you goose the throttle how far does the pressure drop?

Almost forgot, with the 1994 3800, you can sit there via a scan tool and watch the cylinder misfires as they happen... You may be able to get close to a cylinder problem if you can pin it to a single cylinder..

Hello JRS, At idle, fuel pres. is 40-50 psi. With throttle cracked it jumps up to ~50psi. Car is well maintained with plugs/wires within 10k miles or so. Does no seem likely to have cylinder/valvetrain failure overnite. Literally drove car 100 miles, garaged, and next morn. problem arose. PS. car has ~170k miles. Thank you for replies, appreciated.



A Cam Lobe Eh?

I am not going to say that its not possible... But virtually unheard of in any 3.8 or 3800 from 86 on up...These are all equipped with roller lifters as well.. This is very far from common on any of the 3800's...

First, the fuel pressure with the FPR unplugged is LOW... This engine should fall into the 41-47 PSI Range with the Vac line connected, at idle you can be a few PSI below 41 Psi, but with the FPR unplugged you should be on the high side and a bit past it...

Also when was the last time the car was tuned up? Plugs wires and the like...

When you goose the throttle how far does the pressure drop?

Almost forgot, with the 1994 3800, you can sit there via a scan tool and watch the cylinder misfires as they happen... You may be able to get close to a cylinder problem if you can pin it to a single cylinder..

I was just recently working on my 94 lesabre and it was doing the same as you describe. I turned out the ecm fuse under the dash was blown. Just something to check before you buy parts.