I suppose the catylitic converter can get restricted too. There are a lot of components in the EGR system. I don't think I have a fuel system problem but it won't hurt to try some injector cleaner. Additionally, my MPG is not what it used to be (20-21 mpg but now only 17-17.5). Diagnostics shows incorrect (insufficient AND excessive) exhaust gas recirculation, hence my changing of the EGR. I am thinking that there is a problem with the EGR or the vacumn and electrical controls for the EGR. The engine seems to pull a little stronger but the stumble is still there. My first work has been to change the plugs and wires as well as the EGR valve. It is most noticable from about 1600 to 2000 RPM when under light load as when maintaining speed on a flat road. My motor also stumbles at idle and up through mid range. That and the fact that I just replaced everything ignition wise and it got worse really has me confused. power is there, just stumbles like a mofo at constant speed and during idle, which tells me it's most likely ignition. I double checked and 99% sure everything is wired correct from the coil pack to the plugs. Standing in front of the truck looking at the engine with the pullies/belt facing you, the 4.0L OHV is oriented like so: Your ideas/input are welcome! Tomorrow I will be testing the alternator for fluctuating output at idle and making sure that I have the right plug wires going to the right cylinders, which brings up the following. However, since the entire ignition system was replaced, I would tend to lean towards it being something else. alternator getting ready to die, MAF sensor acting funky, TPS (doubt it would cause this, but who knows).Ĥ) It's not worse, just more pronounced now that the rest of the ignition system is firing away perfectly. How would I test the pump?ģ) It's electrical prior to the coil pack: Could be a multitude of things.
I have the fuel filter and plan on replacing it this weekend. definite misfire.ġ) It's mechanical: I have no way to do a compression test to confirm that a cylinder(s) is/are going down (valves, rings, ect.)Ģ) It's fuel related (not sure now) and it's getting worse (faulty injector and/or faulty FPR and/or clogged fuel filter and/or faulty fuel pump). I got out of the car and sniffed the tail pipe. almost to the point of dying at times, like if you unplug the Idle Air Control Valve. Well, after about 2 hours of work, I replaced the coil pack, gapped and installed all 6 plugs and plug wires, replaced the idler pulley (squeeky) and the tensioner pulley (also squeeky).īefore it would only misfire at a constant RPM in mid-low RPM range (cruise control set at like 35-55). If that doesn't work, what should I attempt next to pinpoint the cause? It's either a fuel or spark issue and I think it's the fuel because the majority of the misfires are occuring in 3 specific cylinders. I plan on starting out with a good fuel injector cleaner at the next fill up. I have a feeling that since this involves a constant RPM, the problem is fuel related. In the course of an hour of testing with AutoTap monitoring, there where a total of over 100 misfires!Īnyone have similar symptoms? What is the most likely cause/solution? I am thinking about treating this the most inexpensive way and working my way up the ladder until the problem is solved. Monitoring the misfire option in the OBD-II scanner revieled a lot of misfires. I hoocked up the AutoTap and found that the car's stumbling corresponds to engine misfires. most pronounced with the cruise control set or doing a steady speed below 60 MPH. The condition is very reproducable by doing a constant speed. At constant low to mid RPM's, the car stumbles pretty often. My 96 Sport 4x4 now has 111,097 miles and is starting to act up.
0 kommentar(er)
