engine jumps at 1500rpm

[silverado122775]

Hello Folks!

Have a questions for your mechanics out there.

2000 Silverado Z71 5.3L. 242K on truck ( not on engine )

I replaced the Fuel filter, changed the oil (synblend) and cleaned the air filter (k&N). Everything was working fine yesterday until I get gas today. Now between 40-45mph or roughly 1000-1500RPM the trucks seems to jump continuously. now if I drop down a gear it is fine. if I floor it, it is fine. idle is fine. now if it is going down hill, I do not feel it. but if I am at a level grade or climbing and am trying to keep it between 40-45mph, it feels like its choking. the RPM jumps up then drops back down. it is a slight continuous jump, but noticeable.

The fuel filter I put it is a A/C delco. Trans was serviced about 10-15k miles ago.

any thoughts?

Thanks

[j cAT]

Originally Posted by silverado122775

Hello Folks!

Have a questions for your mechanics out there.

2000 Silverado Z71 5.3L. 242K on truck ( not on engine )

I replaced the Fuel filter, changed the oil (synblend) and cleaned the air filter (k&N). Everything was working fine yesterday until I get gas today. Now between 40-45mph or roughly 1000-1500RPM the trucks seems to jump continuously. now if I drop down a gear it is fine. if I floor it, it is fine. idle is fine. now if it is going down hill, I do not feel it. but if I am at a level grade or climbing and am trying to keep it between 40-45mph, it feels like its choking. the RPM jumps up then drops back down. it is a slight continuous jump, but noticeable.

The fuel filter I put it is a A/C delco. Trans was serviced about 10-15k miles ago.

any thoughts?

Thanks

sounds like you put water instead of gas in it. put 2 bottles of dry gas see whats up. if it works go to that gas station and have then give you cash for the cost of the fix.

[silverado122775]

Originally Posted by j cAT

sounds like you put water instead of gas in it. put 2 bottles of dry gas see whats up. if it works go to that gas station and have then give you cash for the cost of the fix.

it is so funny you say that. because I do not normally go to that gas station, because there price is a little too low.. if you know what I mean.

thanks

[2000CAYukon]

Double check that K&N Oil did not get on the MAF Sensor wires. If so, use MAF cleaner to get the oil off.

//2000CAYukon

[j cAT]

Originally Posted by silverado122775

it is so funny you say that. because I do not normally go to that gas station, because there price is a little too low.. if you know what I mean.

thanks

It can happen at any gas station. could be they did this to make some extra money. if it is bad gas it should be reported. contact the oil company supplying the fuel.

could also be leaking fuel tanks .

I see you are with bosch +4 plugs in this engine . I would replace with ac delco iridium type. these work better than the Bosch plugs. I used the bosch plugs in the past .

[silverado122775]

Originally Posted by j cAT

It can happen at any gas station. could be they did this to make some extra money. if it is bad gas it should be reported. contact the oil company supplying the fuel.

could also be leaking fuel tanks .

I see you are with bosch +4 plugs in this engine . I would replace with ac delco iridium type. these work better than the Bosch plugs. I used the bosch plugs in the past .

Thanks for the heads up.I will re clean the maf sensor.

I have had the Bosch for over 10+ years. Thinking of switching to the new E3 plugs.

Did some research. Thinking it may be the fuel pressure regulator, may be a partial cause at least.

[j cAT]

Originally Posted by silverado122775

Thanks for the heads up.I will re clean the maf sensor.

I have had the Bosch for over 10+ years. Thinking of switching to the new E3 plugs.

Did some research. Thinking it may be the fuel pressure regulator, may be a partial cause at least.

the E3 plugs may work great in a chain saw but not in our engines. many have had bad issues. I would try the ac delco iridium plugs since these have proven by form members to be the best. my study of the reason for this is the fact that iridium can take the heat damage better than other materials like platinum. the design is for a hotter spark and when your engine is cold you should see a better performance. I also got slightly better MPG. I did not have any problems with the bosch plugs for me. just that the iridium plug tips do work better. the E3 well just stay away from those in this engine.

so the gas treatment did not work you still have this problem ?

[silverado122775]

Here is my update:

I added 1pint of seaform into the gas tank. before I got home I already saw improvements.
I went ahead and replaced the fuel pressure regulator. I feel no symptoms now. I think bad gas was the main culprit with the combination of the fuel regulator showing signs of going bad.

Thanks for everyone's help. it is why I like this forum.

[j cAT]

Originally Posted by silverado122775

Here is my update:

I added 1pint of seaform into the gas tank. before I got home I already saw improvements.
I went ahead and replaced the fuel pressure regulator. I feel no symptoms now. I think bad gas was the main culprit with the combination of the fuel regulator showing signs of going bad.

Thanks for everyone's help. it is why I like this forum.

seafoam is used to clean the fuel system it is a solvent.

dry gas is to breakup the water so that you can burn off the water with little engine issues. like I stated before the dry gas is what I would have used. you probably needed the seafoam anyway. should have used it before replacing the fuel filter. now the seafoam is cleaning out the tank to deposit the debris in the filter.

any fuel issues or thoughts of one , you use a fuel pressure gauge and go threw the pressure test procedure to see if you have any fuel delivery issues.