car reving 1000 RPM more then usual

[lachachmtl]

hi guys.i had stored my buick grand national 87 for the winter last year,when i took it out ,i noticed it was reving 100 RPM more then usual.i didnt drive it all last summer cause of $$$ issue now i retook it out for the summer and its doing the same thing.

at 60MPH/100KM its reving 4000 RPM on Drive and 3000 RPM on overdrive.

it used to roll at 60MPH/100KM, 3000 RPM on Drive and 2000 RPM on overdrive.

so now its reving 1000 RPM more then usual,why is that?


possible cause i tought of; maybe a disconnected vacuum hose,maybe a damaged throttle cable, maybe the torque converter dosent lock up anymore.

you could email me directly at lachachmtl@hotmail.com

please find a solution.

ps.from a desperate grand national owner.

 

[lachachmtl]

. the Tachometer is wrong.

we checked the lock up and it works fine ,then hooked it up to a scan and it is showing 1000 RPM more then what the scan reads.

i cant beleive that is the problem.

how do you actually fix this problem now?is it worth fixing or expensive?