HELP! figure this one out! 4.3 lurching and falling

[SAATR]

When a cat plugs, you'll usually notice a reduction in top end power, followed closely by the engine not being able to rev past a certain RPM. It is POSSIBLE, but I'm going to say that is not your problem, given that you still have top end and have just lost mid range power. Check your fuel pressure KOEO, then KOER at idle, then tape the gauge to the windshield and drive it on an empty stretch of road or large, deserted parking lot and monitor you pressure at cruise, WOT and light acceleration. See if it falls off when you lose power.

 

[Tinbender59]

more than likely it is the fuel pressure, does not have enough pressure to sustain a long acceleration run. but it jumps out then falls, then jumps out, and falls again....... also could be an over active knock sensor yanking the timing back would act the same way.

 

[wvk1500]

well, got an appointment to have it put on a diagnostic machine this week coming, will keep everyone updated.

 

[SAATR]

Ah Guten! Can't wait to hear what the culprit is! Hopefully something cheap and easy (one can dream, right?).

 

[wvk1500]

well went to get it analyzed one shop did not have the right plug and the other shop told me to pull the bed and check the rubber lines between the pump and metal line. Supposedly he had 3 trucks come in with the same problems and that was the fix. So after checking my tools i need some long extensions which i have to get yet. I did a little test that I found on the web and had some interesting results. After warming the truck up and like always the problem came. I used a big bolt to plug my brake booster off and the truck seemed to run a little better. I test drove it 3 times and it did not die once but you could tell the problem was still somewhat there. It would fumble but recover which it would not recover before unless you clutched it. By all this testing and sweating man its hot here the temp gauge was well warm enough the truck was still running so I will be checking for other vac leaks along the frame and tank when I pull the bed.