89_trailboss Posted February 14, 2007 Share Posted February 14, 2007 89 VG30I truck starts great. runs fine when you granny it. have nice power. but at ~2500RPM I get a bad stumble/heavy hesitation(only when you are on the gass good). I can cruze the highway with no problem. but when ever I get on the gas I have this heisitation. So what I do Is jsut punch it and get it to down shift -- thus getting me out of the 2500-3000 range and my truck fine. unless your really heavy and then it stumbles at 3500 up. this started when I was low on fuel. but I wasnt THAT low. I have been lower. so my first thogh was that I sucked somthign up into the fuel filter. swapped filters and still have it. maybe because im not running a filter? nope. put one in and the same thing happens. any idea's? Im thinking that my fuel pump is starting to kick the bucket. Link to comment Share on other sites More sharing options...
89_trailboss Posted February 14, 2007 Author Share Posted February 14, 2007 also, I just did plugs, wires and PCV on the weekend. im going to check the plugs and see maybe if one came loose??? also check the wires. Link to comment Share on other sites More sharing options...
89_trailboss Posted February 14, 2007 Author Share Posted February 14, 2007 meh, think I found it. fuel line right near the tank is leaking. frame is all wet. ill fix that and see if anything changes. Link to comment Share on other sites More sharing options...
88pathoffroad Posted February 15, 2007 Share Posted February 15, 2007 Clean your MAF sensor too. Link to comment Share on other sites More sharing options...
89_trailboss Posted February 15, 2007 Author Share Posted February 15, 2007 well, fixed the fuel leaks. yes plural pssd still have it. it seems to be getting worse-affecting more of my RPM range as this goes on. doesnt get worse when its cold or hot. same shhit no matter what. pissed cause I have a trip on sunday and I dont think im gona be able to wheel much with this problem. ill clean my MAF tommorow. altho it was just cleaned 3 months ago. im going to put my old wires back on tommorow and see what happens. any way a fouled spark plug/plugs could cause this stumble/hesitation? im going to snag a fuel pressure gauge tommorow and see if my pumps gone. last time I check my codes(month ago) I had the ignition signal code(11 or 21 IIRC) and my dreaded 02 sensor code was back. if I have good pressure ill swap 02's but I dont think this is the problem. possable vacuum issue? I know I put a slight crack in my PCV tube. but it wasnt anything that I worried about cause it was SOOOO small. and I put some RTV on the PCV to help seal and possable issue. Im sure this is a fuel problem tho. any other ideas? Link to comment Share on other sites More sharing options...
88pathoffroad Posted February 15, 2007 Share Posted February 15, 2007 From what I've seen, fueling is rarely an issue unless the ECU error codes have a code stored for a leaking or misfiring injector. Most of the time poor idle/throttle response is from bad sensors or vaccuum/air leaks. Link to comment Share on other sites More sharing options...
89_trailboss Posted February 15, 2007 Author Share Posted February 15, 2007 it idles fine. jsut seems to chung under load. I cant pin it and the RPMS will go to say 4500 and stay there cause the trans is in POWER. when its just sitting at the said 4500 it runs fine. but any bit of gas it will stumble. pulling codes as we speak. well, in a min. Link to comment Share on other sites More sharing options...
mws Posted February 15, 2007 Share Posted February 15, 2007 Do not delete the MAF sensor from your list of suspects - what you describe is consistent with problems with it. It's not sounding RPM related so much as an inability to correctly adjust fuel for changing air intake. Link to comment Share on other sites More sharing options...
89_trailboss Posted February 16, 2007 Author Share Posted February 16, 2007 I agree. its not RPM related. from my past experense with other vehicals this feels like a fuel problem. my buddies B2 had very similar problems but his truck would stumble so bad it would stall. swap fuel pumps and it was fine. but eveybody on the web thinks its somthing else. anyways, I pulled the codes and got 13 and 21. ive never gotten the engine coolent temp sensor(13) code before. always had the 21 tho. could 13 cause these problems? for some resone I think I heard about it causing problems. but I cant seem to remember if it was running problems or if it was removal on the VG30E motors that was the problem. thanks for the help guys. Link to comment Share on other sites More sharing options...
mws Posted February 16, 2007 Share Posted February 16, 2007 I think it could. Basic concept of fuel injection: The ECU uses lots of inputs to determine how much fuel the engine would need under the conditions at this millisecond. Then it looks at what the O2 sensor is saying as to whether it is too rich or too lean and adjusts the mixture closer to ideal. Keep in mind that the feedback from the 02 sensor can adjust only so much. So if ANY of the key sensors are faulty, they will give the ECU faulty information and it is going to squirt too much or too little fuel. So any sensor can cause a "fuel delivery" problem. A faulty water temp sensor? If the sensor is telling the ECU that the engine is cold, the ECU is going to squirt a very rich mixture, and the feedback from the O2 will never be enough to make it right. Link to comment Share on other sites More sharing options...
89_trailboss Posted February 16, 2007 Author Share Posted February 16, 2007 got a pressure gauge. will check right away. picked up an 02 sensor and cap/rotor so ill swap those out and see whats what. Link to comment Share on other sites More sharing options...
89_trailboss Posted February 17, 2007 Author Share Posted February 17, 2007 fuel pressure is good. 36 PSI at idle and load. im going to put the truck back to the way it was a week ago and see what its like(orginal plugs and wires. well wires first). damn this sux Link to comment Share on other sites More sharing options...
89_trailboss Posted February 17, 2007 Author Share Posted February 17, 2007 went back to my old wires. same thing. pulled plugs. passanger side was super rich(plugs were really black) drivers side they were ok. whats up with that? Link to comment Share on other sites More sharing options...
88pathoffroad Posted February 17, 2007 Share Posted February 17, 2007 The PVC valve is on that side. Perhaps it's pulling an excessive amount of oil vapor through the PVC valve into the intake as part of the problem? Link to comment Share on other sites More sharing options...
89_trailboss Posted February 18, 2007 Author Share Posted February 18, 2007 jesus christ. feel like a fawkin IDIOT! so I had the stuble while driving but it would idle fine and would drive fine if I grannied it. in the prosses of finding the issue I replaced the Cap and rotor. as soon as I did this the truck had a heavy miss. I replaced plugs and wires AGAIN. still same stuff. MAF and coil changed AGAIN. still same thing. got pissed and left it today and went out for dinner. on the way to dinner it dawned on me. some how I managed to put my #4 and 6 plug wires on each other(4 on cap went to 6 and visversa). so I turned around and went back home quickly. swapped them around and sure enough the thing idle fine! and in the prosses of trying to figure out the rought idle I replaced somthing that fixed my stuble while driving. YAY! Just in time for sunday wheeling. thanks for the help guys. one more thing tho. how many degrees is each timing mark? Link to comment Share on other sites More sharing options...
88pathoffroad Posted February 18, 2007 Share Posted February 18, 2007 Five I think, innit? Link to comment Share on other sites More sharing options...
89_trailboss Posted February 18, 2007 Author Share Posted February 18, 2007 cool, thats what I though too. Link to comment Share on other sites More sharing options...
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