Shacks, rattles and DOSEN'T roll !!

[Fire54Medic]

HELLLPPPP !!! Ok, This is the first time on asking a question and for help online, but here goes. I have a 1999 Chevrolet Tahoe 2wd, 5.7 Vortec. Mileage unknown. I have changed the cap & button, spark plugs and Cam shaft position sensor. The reason I have done all these, is at around 70 mph, It starts to shack, (enough to where I have to let off gas) and misses, throws a SES code (misfire cyl. 3 sometimes cyl. 5) and acts like it boggs down, like no fuel, then catches back up like normal. Or when I pull out from like a store and give it gas it boggs down and doesn’t go anywhere till I let off the gas then get back in it..if I stay in it, it will back fire. I drive to and from work, around 200 miles 3 days a week. It will drive fine on straight stretches, but it seems like it only does this up a hill or rise. By the time I get to a parts store to read the code, I have driven on a good straight shot and the SES goes off, and no code are present. I’m tired of playing a guessing game, replacing an item to see what might fix it. Can someone please help me on what can be done next…ughhh..

 

[2Canoes]

Have you tried a new fuel filter?

 

[Donnie Yukonie]

Moved this to Engine and Drivetrain ,

As for your problem Have you checked your Fuel pressure?

 

[Fire54Medic]

Fuel Pressure good tested not to long ago, fuel filter changed also forgot to mention. Also I just did this on way back from store. It started shacking going up a small hill, so I pulled it down in neutral and it quit immediately, put it back in OD, started again when giving it gas, Neutral-stopped again, this time put in drive (3rd)- started shaking..got to top of rise and straight stretch it smoothes out and stops..When I went to town didn't do anything.

---------- Post added at 12:57 PM ---------- Previous post was at 12:56 PM ----------

Moved this to Engine and Drivetrain ,

As for your problem Have you checked your Fuel pressure?

Fuel Pressure good tested not to long ago

 

[Gzes]

Does it have enough gas? On my del sol when is low it does that. My fuel guage doesn't work so that's how I know It needs gas

 

[retorq]

Del Sol's are slow pieces of poo

thetruth.com

 

[Fire54Medic]

Yeah, plenty of fuel, does it on full tank and anywhere in between...

 

[retorq]

You didn't say spark plug wires, check those, they can be bad but look fine ...

 

[2Canoes]

When I think I might have a bad wire or coil, I wait until it gets dark and look at the engine while it's running. Just look for the spark. You probably knew that trick, but if you didn't...

 

[SunlitComet]

Verify fuel pressure again and when you are at the parts store have them plug in again and if possible search for pending or stored codes if they can. Also see if they can see live data and verify that the scanner rpm readout matches the dash tach at randomly selected throttle positions. It does sound like your pressure is off. Tho since you mention it happens on inclines it makes be think a valve is sticking.