When i'm driving and it goes to shift (auto) it sort of stumbles, hesitates(sometimes backfires) shifts, then runs fine. Idles fine and all. Replaced the TPS sensor a while back, it was faulty. Any ideas guys? it has no cats, so clogged cat eliminates that possibility..It's really bugging me and iv'e research this issue and alot say cam position sensor??? Help... Trying to sell truck, it wont sell this way-

Thanks!!

 

Check fuel pressure..... possibly cam sensor... but, I don't see why it would only do it when it wanted to shift....

clean your battery terminals as well.

 

fuel pressure is good,battery terminals clean, havent done cam sensor, how does this correlate with shifting?

 

Not saying it's your problem, but just because you eliminated the cat(S) does not mean you eliminated the plenum problem. Anyway, besides that I'd maybe take a look at the crank sensor and o2 sensor.

 

the cat(s) were not clogged. I could see daylight threw them, every little square was perfectly boxed. on both cats-I removed them because a few months ago i had a multi cylinder misfire, and in turn this poisoned my cat.Failed inspection, whole 9 yards..But before i add a new cat on there, i want to fix my current issue.Any help is appreciated.

 

I had this exact problem for a couple of months, it was a bad distributor cap .

 

it only acted up when shifting?????

 

if it is the cap, i will flip S*** bought all tune up parts at same time at autozone, spark plugs were faulty and now this?

 

When was the last time the cap and rotor was replaced? Get a brass terminal cap. Loss of power causes all kinds of problems . It's worth a shot as Pacman suggested.

 

about 4 months ago, less then 6000 miles..