Hesitation at highway speed

[krfloors]

OK here is the deal. I have a 99 Tahoe 4x4, 5.7, with a k&n filter system, 101,000 miles on it. My hoe has a hesitation at 70 miles an hour. When I put the throttle down to pass someone it sounds like it is flooding or missing. Yesterday I changed the fuel pump, fuel filter, all 4 o2 sensors and it still does this. It is always right around 70 and when I have to push it a bit. It sounds like it is missing. I have no idea. Any ideas would be great. Thank you.

 

[mygreen98]

is the ses light on? possible injector problem. or maf problem.

 

[krfloors]

The ses light is not on at all. It idles fine and never hesitates at low speeds. What is the MAF?

 

[96ProCompTahoe]

MAF= Mass Airflow Sensor

 

[mygreen98]

how old are plugs, cap, rotor wires. pull all plugs and inspect, see if any are fouled, incorrect gap or have deposits on them. check wires for arcing, pull cap and check inside terminals for corrosion, rotor too.

 

[krfloors]

ok now I have an ses light on. I will probably take it and have it read tomorrow. I will post back and see what you all think.

 

[mygreen98]

is ses on steady or does it flash?

 

[krfloors]

it is on steady.

 

[mygreen98]

ok, if it were flashing, this would be a complete misfire on one or more cylinders. check the codes and post findings, good luck.

 

[krfloors]

OK took it to autozone they hooked it up and it came back with an EVAP leak which they said is usually a gas cap issue. Well I have a new gas cap on this thing so I done think that wouls be it. SO I took it home and went over everything looking for a vacuum leak but could find nothing.

 

[krfloors]

I had it out on the highway last night what happens is when I punch it and get up to around 75mph and let off for a second then go back into it a bit is when it happens. Just spits and sputters.

 

[jimbo98]

same stuttering problem

My 98 with 130k miles does the exact same thing. I got the SES light and read the code as "engine misfire" . Changed plugs,wires,fuel filter,cap and rotor. Stil chugs when i have a trailer behind or slowly accelerate. Im thinking about changing the ignition module. Wanting this cured.