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About mzavala

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  1. Thanks, I'm still going to buy a gauge to have for future but I took the gamble already & it was my lucky day, got it all button up & it's working perfectly. Now I have to shop around for cats that are carb approved. Thinking about registering another state as long that it's not California, evetything is more expensive here in Ca registration, insurance & now the Ca approved cats.
  2. Yes I agree with you on the part of the O2 sensor reading non-realistiic exhaust value, causing the ECM to adjust incorrectly, but for a rough diagnosing of the problem it works great, like it did in this case. But I also used the odds factor, by that I mean, for example, bank #1 had most of the multiple missfire & the codes that would show up more consistent were for bank #1, so I loosened the header pipe for bank #1. With that I knew for sure it was a restriction in the exhaust, but here again I went with the odds when I decided to gut out the cat. Realistically it could have been the resinator, muffler or even the pipe itself. So I just done a outer visual inspection of everything past the loose header, I didn't see anything that stood out so I went with gutting out the cat & thank god it turned out to be the right choice. Also I think even if the computer adjust the maximum it's parameters, I'm pretty sure it wouldn't drive like it had been driving lately. Don't get me wrong, I totally agree with what you're saying, where we might have a slightly different opinion is on how much the exhaust leak will afect the drivability. But hey, before I forget, I really want to thank you, you were great help, & I hope you don't take my explanation the wrong way, I can see your a knowledgeable person in this field, I know for a fact that you are way more advance than I am. I look forward to receiving your input on my future problems (I'm sure I'll have plenty), Thanks again, Mario
  3. The problem started mild loss of power to barley drivable within a week. I got it figured out, after replacing ignition coils & wires I took for a spin & again it was hard to get it to go over 20 mph, made it back & pulled the codes, it had P0101, P0300, P0324 & P0331. I looked up code P0101 & seen it was pretty common for GM vehicles that had a P0101 code to have a problem with the exhaust being restricted. So since I don't have a back pressure gauge & couldn't find a cheap one here in town, I I loosened the exhaust for bank #1 at the flange where header pipe bolts on to exhaust manifold, & bingo, I drove it with the exhaust leak & it drove perfectly. Of course I got s code for O2 malfunction but the truck had power no more sputtering or dying down on hard acceleration! So what I'm doing now is drilling the cat to gut it out, so I can use the truck while I order & install a new cat, wish I didn't have to buy a California approved cat. But I have to get it smog in Ca so I have to pay extra Ca ARB cert. Thanks everyone & hopes my little adventure helps someone else diagnose there car\truck.
  4. Thanks, I'll check that. I also just noticed that the new plug wires (cheap Duralast) are worse than the old ones, the new ones has 2330 ohms & the old wires measure 785 ohms, I think I'll go buy some good wires & new coils, since I have about 135k miles them it can't hurt to install new ones. And I'll see what I can find with the wiring while I'm in there.
  5. Well the spark plug cables didn't help as a matter of fact I barely made it back from the test drive, & with a bunch of new codes. Now it's showing: P0068.00 P0101.00 P0300.00 P0324.00 P0326.00 P0331.00 Two things I forgot to mention I already replaced the maf sensor & also when I first got the knock sensor code P0324, I unplugged the harness at the sensor & check voltage on both wires w KOEO & I only got 1.3 volts on one side & 1.8 volts on the other I wiggled the harness a bit to see if voltage would change but stayed the same. I haven't probed all the way back to the ECM, but I'm starting to wonder if I have a bad ECM since I'm getting all these different codes poping up sometimes, the only code that's faithful is P0300, this one is all the time, the other some times the show as pending & some times nothing but P0300 or P0300 with a whole new code
  6. Yes, that's what I thought but wanted to verify. & Yes I put a long extension hose on my fuel gauge & test drove it down the highway & the pressure was constant at 65psi maybe 2-3 psi for a second or two but basically 65psi all the time. Right now I'm changing the spark plug cables, I didn't believe itcould b the cables because my thinking was how could multiple wires ho bad all at the same time, but I'm comparing old wire versus new with ohm meter & there seems to be a big difference. Iknow in a little bit once I test drive it. Thsnks for your input on the fuel pressure drop that helps me move on & look somewhere else for the problem! Thaks again, Mario
  7. Hello everyone, First off I want to thank you for letting me join your forum, hope I can be of some help to the community. But for now I'm hoping somebody can help me out with the following problem. I have a 2013 Silverado 2500HD, 6.0 lt eng. 4X4, I have a terrible loss of power, when symptom started it would start losing power, sputtering & feels like either lack of fuel or too much fuel, at 4k rpm's +, but now it's doing it at lower rpm's. I'm getting various codes on my scanner but I'm always getting code p0300. The other codes I'm getting are knock sensor p0324 a few times & one time p0331. Just yesterday I also got code p0157 & p2099. A recap of what I have tested, I set my scanner on to misfire diagnose & just about all cylinders are showing misfire fault with the the highest faults being cyl #5 with 458 faults, #6 with 240 faults & #1 with 156 faults, the other showing faults in the 10's or 20's. The other thing I check & found a problem was, fuel pump pressure, the pressure is at 65 psi (which I believe is within specs) but as soon as I turn off the ignition the pressure drops rapidly, like 20psi drop in 30 seconds. Here is were I have a doubt, I've had this problem on other cars but the symptoms on those occasions was initial hard start until they built pressure back up. But does anyone know if this pressure drop can also cause my power loss sympyoms? By the way I also disconnected fuel supply hose at the rail & applied 60psi to the rail and injectors & it held pressure perfectly for about an hour or more. The hose looks good so I think its the check valve or pressure regulator in tank that's letting it leak back into tank. Thanks in advance for any help given, Mario

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