Engine hesitates

[El_Callao]

My 2003 suburban 1500 LT RWD starts shaking inside the cabin when AC is on and also hesitates when the AC is on. I’ve already changed the plug Wire and spark plug and cleaned the MAF and throttle body as well but it’s still doing the same thing. No check engine light is on.


PLEASE ANYONE HELP!!

 

[swathdiver]

My suburban starts shaking inside the cabin when AC is on and also hesitates when the AC is on. I’ve already changed the plug Wire and spark plug and cleaned the MAF and throttle body as well but it’s still doing the same thing.


PLEASE ANYONE HELP!!

It might be time for a new compressor. Really need to put a scan tool on it to check the throttle body.

 

[OR VietVet]

Like @swathdiver said, the a/c is a sizeable load on the engine when it comes on and if the throttle body sensors are not sensing the load correctly it can cause the engine to be sluggish and if there is a problem with the compressor itself, it can really cause havoc. I am assuming no CEL?

It sure would help to post the vehicle info in case there is a year or two that had similar problems that we can track down. See our signatures?

Welcome to the forum from Oregon.

 

[El_Callao]

It might be time for a new compressor. Really need to put a scan tool on it to check the throttle body.

No check engine light is on and it runs perfectly when it’s off.

 

[El_Callao]

Like @swathdiver said, the a/c is a sizeable load on the engine when it comes on and if the throttle body sensors are not sensing the load correctly it can cause the engine to be sluggish and if there is a problem with the compressor itself, it can really cause havoc. I am assuming no CEL?

It sure would help to post the vehicle info in case there is a year or two that had similar problems that we can track down. See our signatures?

Welcome to the forum from Oregon.

So you think it could be the compressor?

 

[OR VietVet]

I "think" that since the problem only happens when the a/c is on, that it is a load condition problem. The a/c coming on is a load against the engine power supply. If the compressor is failing it can try to partially lock up and really pull against the engine power. The compressor may be just fine but something in the fuel system may be effected with the pull of the a/c compressor when the a/c is turned on. I apologize if I just missed the year and model of the rig in the first post but if you just added there and did not say, that was pretty sneaky or I am just old. Engine size is 5.3, right? Mileage?

When you say it shakes inside the cabin, what does that mean? Shakes where? Feel shakes where? Does rpm fluctuate at the same time? Hesitates just from stops or anytime you accel? Effecting power on the road at any speeds?

 

[El_Callao]

I "think" that since the problem only happens when the a/c is on, that it is a load condition problem. The a/c coming on is a load against the engine power supply. If the compressor is failing it can try to partially lock up and really pull against the engine power. The compressor may be just fine but something in the fuel system may be effected with the pull of the a/c compressor when the a/c is turned on. I apologize if I just missed the year and model of the rig in the first post but if you just added there and did not say, that was pretty sneaky or I am just old. Engine size is 5.3, right? Mileage?

When you say it shakes inside the cabin, what does that mean? Shakes where? Feel shakes where? Does rpm fluctuate at the same time? Hesitates just from stops or anytime you accel? Effecting power on the road at any speeds?

Do you think fuel injectors or coil pack? & No I just added , but 5.3 and mileage is 215,435, The shakes/ vibrating is like center console, steering wheel seats and buckets seats in the back & just when it’s on a stop

 

[OR VietVet]

So, even at my age I thought I did not see the vehicle info. You are sneaky.

I don't see a problem with injectors or coils if you have no problems off idle. I am surprised that there is no CEL. Maybe a fuel pressure regulator but I am not convinced of that. I am leaning more toward maybe a TPS. Hopefully others here will chime in and help.

 

[El_Callao]

So, even at my age I thought I did not see the vehicle info. You are sneaky.

I don't see a problem with injectors or coils if you have no problems off idle. I am surprised that there is no CEL. Maybe a fuel pressure regulator but I am not convinced of that. I am leaning more toward maybe a TPS. Hopefully others here will chime in and help.

Hopefully cause I’m tired of not being able to turn on the AC when its 90 degrees

 

[ks03]

My go to for how this sounds is spraying to look for manifold vacuum leak.
any other recent work? Ac performing similarly to how it has been?
Slip the ac belt off and see if the tensioner pulley sounds rough.
From there I’d want a scanner of some sort, make sure there’s no codes stored, where the fuel trims are when it’s acting up, and sometimes you can see a response spraying the intake that you can’t hear