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Is the check engine light on while driving?
When driving, does it seem like the transmission takes off in first gear, then shifts to second and third, but will not shift into fourth gear?
If this is the case, when driving in third gear, pull the shift lever down from the overdrive position to the drive position and see if you note any difference in rpm. Let me know what you find.
when it shift out of third gear the rpm rise up like it is in netural.i just will not go into fourth gear. i guess i will have to replace the transmission. charles