99 yukon bucking sluggish ride, help..!!

[rell_ent]

I have a 99 Yukon that the check engine light had came on and i took it to the dealership, they replaced my fuel injectors. Soon as i left i noticed that the truck would buck while driving and when the truck would down shift. It also seems like a sluggish ride with a hesitation type of a feel and powerless. Then took the truck back down to the dealership and they kept telling me its the torque convertor, which i thought was funnie that it would just go bad right after they fixed something else. So i finally gave in and just had a reman. trans put it and the problem is still their.. and ideas im lost..?

99 Yukon
80,000 miles
fresh rebuilt engine
fresh rebuilt trans
new fuel pump

Problem was first noticed after they replaced my injectors..

 

[BrianBrianBrian]

Very similar scenario happening...

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[bunchz71]

ANy issues starting ? Does it start like it should or does it have to turn over several seconds before it does ? Could be a weak fuel pump/dirty fuel filter. Check your fuel pressure with key on and engine off. It should be around 60# if I am not mistaken. If you are not getting at least 60# of fuel pressure with key on engine off, I would suspect that your fuel pump is not strong enough to keep all cylinders supplied with fuel when engine is running.

 

[bunchz71]

ANy issues starting ? Does it start like it should or does it have to turn over several seconds before it does ? Could be a weak fuel pump/dirty fuel filter. Check your fuel pressure with key on and engine off. It should be around 60# if I am not mistaken. If you are not getting at least 60# of fuel pressure with key on engine off, I would suspect that your fuel pump is not strong enough to keep all cylinders supplied with fuel when engine is running.

Just seen your new fuel pump .... lol

New doesnt always mean good. I would double check pressure and make sure you have a clean fuel filter as well.

 

[rell_ent]

Just seen your new fuel pump .... lol

New doesnt always mean good. I would double check pressure and make sure you have a clean fuel filter as well.

ok ill look into that, i just want to add that, i picked the truck up from the dealer ship yesterday and she ran find the receipt said they replaced #3 coil. cap and rotor. #3 cylinder was found to be misfiring. Left out this morning for work at 430am when it was nice and cool the truck ran like brand new money 100 in the fat land with no problem, but when i got off work in the 80+ degree weather is when it got sluggish and bucking etc. especially when the truck down shifts gears..