91 5.7 tbi hesitating under Accel/turning

[bambam78]

Hey guys, back again with Another problem lol, truck has 100,000 miles on the motor

Here recently when my truck is cold it has a hesitation when I accelerate, if you punch the gas it will fall flat on its face, then it will pick back up and act normal As it warms up, it also hesitates when you pull out of a sharp turn, usually right after it shifts into 2nd gear, it's not a huge problem, just annoying

Also has a fairly rough idle, feels like it has a miss or somthing


So far I've replaced
New plugs
New rotor/cap
Fuel pump <20,000 miles
Fuel filter < 20,000 miles
Spark plugs < 10,000 miles
Iac valve
Tps
Cts
Rebuilt throttle body
Map sensor
O2 sensor


Anybody got any ideas?

 

[96-1500]

Plug wires and cap/rotor for sure if you've already gone that far

 

[bambam78]

Changed plug wires/cap And rotor with no change, any more ideas guys?

 

[SAATR]

Have you checked your fuel pressure? I know it's a pain to build an in line adapter to fit the truck, but it really sounds like a fuel pressure/starvation issue.

 

[skl727]

Hey guys, back again with Another problem lol, truck has 100,000 miles on the motor

Here recently when my truck is cold it has a hesitation when I accelerate, if you punch the gas it will fall flat on its face, then it will pick back up and act normal As it warms up, it also hesitates when you pull out of a sharp turn, usually right after it shifts into 2nd gear, it's not a huge problem, just annoying

Also has a fairly rough idle, feels like it has a miss or somthing


So far I've replaced
New plugs
New rotor/cap
Fuel pump <20,000 miles
Fuel filter < 20,000 miles
Spark plugs < 10,000 miles
Iac valve
Tps
Cts
Rebuilt throttle body
Map sensor
O2 sensor


Anybody got any ideas?

I have a 95 GMC Sierra XC 5.7, the stumble that I had was 99% relieved when I replaced my EGR valve. Hope it helps....

 

[magimerlin]

Check you grounds!!!!!!! My 94 was doing that and I found that the ground between the body and the engine had broken. Not all your sensors are grounded on the engine. Some are grounded via the body. I replaced just that ground and it fixed all the issues I was having. I ended up building all new bigger grounds.


Sent from what use to be a great country.

 

[magimerlin]

3 main grounds are

Battery (-) to engine block
Battery (-) to truck frame
Rear of engine block to firewall.


Sent from what use to be a great country.