Miss after heavy acceleration

I have a '99 Yukon SLT with 123,000 miles, 5.7L, 4WD. A couple of years ago I had 2 injectors replaced to cure a miss that occurred after heavy acceleration, such as when merging onto an interstate from a ramp. The miss has returned, and I'm looking for a way to avoid the nearly $900 charge it took to fix it again. (The heads have to be removed). Is there a good injector cleaner I can put in the gas to clean the injectors, or is that a waste of money? I just put in some this morning (Greased Lightning brand, I think). It misses only after I have quit accelerating and resume with light throttle. I think the plugs and wires are OK. It otherwise runs fine -- starts quick, accelerates well, idles and runs smoothly. What causes the injectors to clog anyway?
Thanks,

You sure its injectors? How can you tell theyre miss fireing without dio?

You sure its injectors? How can you tell theyre miss fireing without dio?

All I know is that it is doing the same thing as when I had the injectors replaced two years ago. At that time, various local shops had put new plugs and wires in and run intake cleaner through it to no avail. I thought it was the transmission, like a torque converter failing, but their diagnostics reported the transmission was fine. BTW, the fuel injector cleaner did nothing. As long as I don't wind it out under heavy acceleration, there is no problem, but if I accelerate strongly going onto an on ramp, for example, then begin letting off the accelerator it will shudder for 10-20 seconds as I let off or give it lighter throttle. I just take it easy until it settles down then resume driving as usual. I don't know what else it could be, unless perhaps a fuel pump malfunction.

It would be nice to know what the fuel pressure is doing when this "shudder" happens. It could be a drop in fuel pressure when you let off the gas. The fuel pressure regulator works off engine vacuum so that could be related.

For problems like this, I have hooked up a fuel pressure gauge and taped it to the windshield so that I could monitor the pressure while the problem occurs.

Another option is to find a shop with a dyno. Then they can watch the fuel pressure when the problem occurs.

//2000CAYukon

I have a '99 Yukon SLT with 123,000 miles, 5.7L, 4WD. A couple of years ago I had 2 injectors replaced to cure a miss that occurred after heavy acceleration, such as when merging onto an interstate from a ramp. The miss has returned, and I'm looking for a way to avoid the nearly $900 charge it took to fix it again. (The heads have to be removed). Is there a good injector cleaner I can put in the gas to clean the injectors, or is that a waste of money? I just put in some this morning (Greased Lightning brand, I think). It misses only after I have quit accelerating and resume with light throttle. I think the plugs and wires are OK. It otherwise runs fine -- starts quick, accelerates well, idles and runs smoothly. What causes the injectors to clog anyway?
Thanks,

I have experienced the same problem. The miss is after the high throtle setting not during. I had good success after using a spray cleaner in the induction system. I don't like better living through chemistry but this worked. I begin to think some airflow instability or seed of carbon in the intake was icing or just making the computer goofy for a few seconds.