Automatic tranny won't kickdown/downshift

[showman]

Car started misfiring and idling rough. Brought to mechanic, had tune-up, new sparkplug cables, new brake booster...now the damn thing won't kickdown when I punch it. I'll be on the freeway doing 65 and when I press all the way down, it just stays in same gear. Didn't do this before I brought it in.

I swear the engine sounds muffled when I punch it - I have headers, flowmasters - I want my power back! Also, it's sporatically hard to start, hot or cold.

Any ideas?

Thanks!

 

[vetteoz]

Start with the TV cable that controls all the trans functions including downshift is adjusted correctly As this controls the trans line pressure driving with it incorrectly adjusted could ( and has done ) torch your trans

 

[dogfish246]

Are there any symptoms when you give it a lot of gas from a stand-still or slow roll?

 

[showman]

No tranny symptoms. But engine wise its lost power. It all started AFTER my mechanic (ex-mechanic now) worked on it. I think I've got a vacuum leak or something is clogged.

I'm going to take it to a tranny shop and have them check it out.

Are there any symptoms when you give it a lot of gas from a stand-still or slow roll?

 

[surfer93]

What year?
Most likely, he accidently knock off or broke a vacuum line.
TV cable is probably fine, check for loose plug or plug wire.
Make sure that the cap is on tight, seen loose caps cause problems.
Make sure coil is connected properly and tight.

 

[ddahlgren]

I did a tuneup on my 91 several months ago and the new AC delco wires were 16,000 ohms. I have no idea what they were thinging 3 times more resistance than the OEM ones. Put on a set of moroso 8mm spiral core wires and all was well again! don't get wires with less than 700 ohms per foot like some of these so called 'super conductors' are as low as 65 ohms per foot and will cause tons of RF interference for all the computer stuff in the car. At least I have had bad luck with them in the past.

 

[TWISTERUP]

Start with the TV cable that controls all the trans functions including downshift is adjusted correctly As this controls the trans line pressure driving with it incorrectly adjusted could ( and has done ) torch your trans

I agree-that's what it sounds like--are you sure it's not upshifting into the next gear at a lower rpm/speed then before? Is the only difference just that it's lost kickdown as far as the trans goes?