Bucking/Hesitating after cruising-- Please Help!

[Red99]

Hi guys. My 99 Vortec Tahoe has recently developed this bucking/stumbling/hesitating issue, and I'm stumped trying to trace it to a cause.
It starts, idles and drives fine in the morning on the way to work, but always on the way home (and coincidentally in almost the same sretch of freeway) it starts bucking and hesitating when I get off then back on the gas, like when you're cruising along and then have to slow down for some light traffic then resume cruising.
The engine otherwise feels healthy, with no other noises or smoking.
What I've done recently tuning wise are:. New plugs, K&N type air filter, installed Dynomax ultraflo muffler (cats still in place), and last week changed the fuel filter. Tonight I pulled out the MAF sensor to inspect, and it's clean.
It really seems like a fuel delivery issue to me. Fuel pump was replaced about 40k miles ago. Maybe there's debris in the tank(?)-- possibly intermittently clogging the fuel line ?
It does have 216k original miles, but like I said, seems healthy otherwise.
Any ideas? Thanks in advance for your help!!

 

[Red99]

Hi guys. My 99 Vortec Tahoe has recently developed this bucking/stumbling/hesitating issue, and I'm stumped trying to trace it to a cause.
It starts, idles and drives fine in the morning on the way to work, but always on the way home (and coincidentally in almost the same sretch of freeway) it starts bucking and hesitating when I get off then back on the gas, like when you're cruising along and then have to slow down for some light traffic then resume cruising.
The engine otherwise feels healthy, with no other noises or smoking.
What I've done recently tuning wise are:. New plugs, K&N type air filter, installed Dynomax ultraflo muffler (cats still in place), and last week changed the fuel filter. Tonight I pulled out the MAF sensor to inspect, and it's clean.
It really seems like a fuel delivery issue to me. Fuel pump was replaced about 40k miles ago. Maybe there's debris in the tank(?)-- possibly intermittently clogging the fuel line ?
It does have 216k original miles, but like I said, seems healthy otherwise.
Any ideas? Thanks in advance for your help!!

 

[Red99]

Anyone???

 

[rell_ent]

Anyone???

im having the same exact problem u described it to a T, im taking it back to the dealership tom. morning as the problem started after they changed the fuel injectors and fuel pump, this is the third time hopefully they can figure it out they have been giving me a hard time..

 

[rell_ent]

Hi guys. My 99 Vortec Tahoe has recently developed this bucking/stumbling/hesitating issue, and I'm stumped trying to trace it to a cause.
It starts, idles and drives fine in the morning on the way to work, but always on the way home (and coincidentally in almost the same sretch of freeway) it starts bucking and hesitating when I get off then back on the gas, like when you're cruising along and then have to slow down for some light traffic then resume cruising.
The engine otherwise feels healthy, with no other noises or smoking.
What I've done recently tuning wise are:. New plugs, K&N type air filter, installed Dynomax ultraflo muffler (cats still in place), and last week changed the fuel filter. Tonight I pulled out the MAF sensor to inspect, and it's clean.
It really seems like a fuel delivery issue to me. Fuel pump was replaced about 40k miles ago. Maybe there's debris in the tank(?)-- possibly intermittently clogging the fuel line ?
It does have 216k original miles, but like I said, seems healthy otherwise.
Any ideas? Thanks in advance for your help!!

any updates on this issue?

 

[res02p35]

This will seem odd but this was happening to me. How I resolved it is unplug the connector on the temp sending unit. My temp gauge still works on the dash so this must be some type of sensor to the computer. Have not tried to fix/ replace that sensor.

 

[Eman85]

If you unplugged the coolant temp sensor for the ECU it is falsely telling it the engine is cold. In turn the ECU will richen up the mixture like it is a cold start. Did the check engine light come on?

 

[Eman85]

As for bucking and hesitating many times it can be an ignition miss. If you suspect a miss and want to check plug wires a simple trick is a spray bottle of water with a little dish soap added. Have someone lightly power brake the vehicle while you mist the solution on the plug wires. When you find the spot the engine will buck and miss.