99ta Posted March 3, 2009 Report Share Posted March 3, 2009 The truck is missing a cruising speeds. changed plugs, wire, cap, button, and fuel filter. pump is only about 3 years old. any ideas? no check engine light. idles fine. i guess the next step is to replace the pump? Thanks Eric Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted March 3, 2009 Report Share Posted March 3, 2009 injector issue or possible vacuum leak at intake gasket Quote Link to comment Share on other sites More sharing options...
99ta Posted March 3, 2009 Author Report Share Posted March 3, 2009 any way to diagnose? or trial and error type thing. Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted March 3, 2009 Report Share Posted March 3, 2009 how bad is the miss? you can use brake clean and go over the intake gaskets too see if you can find a leak. if no leak i would suspect a injector/nozzle issue. you could try omhing the injector's out(easy to do thru the top connector) but if the nozzles are clogged that wont show it. checking the fp and the intake gaskets would be your best bet to start with. Quote Link to comment Share on other sites More sharing options...
99ta Posted March 3, 2009 Author Report Share Posted March 3, 2009 its not bad but I can def feel it while cruising. not so much during acceleration. I will try a new injector to see if that fixes it. thanks rob. Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted March 3, 2009 Report Share Posted March 3, 2009 its not bad but I can def feel it while cruising. not so much during acceleration. I will try a new injector to see if that fixes it. thanks rob. theres 8 of them..which one you going to try? or does that have the one big one in it? also, when you take the top off, and if you see fuel just sitting in there, the regulator is leaking. and it will need replaced. Quote Link to comment Share on other sites More sharing options...
99ta Posted March 3, 2009 Author Report Share Posted March 3, 2009 I believe it just has the one big one, could be wrong though. Quote Link to comment Share on other sites More sharing options...
coryscobra Posted March 3, 2009 Report Share Posted March 3, 2009 Just spray it. Quote Link to comment Share on other sites More sharing options...
Cordell Posted March 4, 2009 Report Share Posted March 4, 2009 I've seen catalitic converters clog up and cause something like your description, but I've also seen that spider injection crap screw up too. Start with what Gearhead said. Quote Link to comment Share on other sites More sharing options...
99ta Posted March 5, 2009 Author Report Share Posted March 5, 2009 I've seen catalitic converters clog up and cause something like your description, but I've also seen that spider injection crap screw up too. Start with what Gearhead said. wouldn't the cat issues cause a code? Quote Link to comment Share on other sites More sharing options...
99ta Posted March 6, 2009 Author Report Share Posted March 6, 2009 ok. fuel pressure is 55. no leak from the intake gasket. this is so frustrating..... Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted March 6, 2009 Report Share Posted March 6, 2009 (edited) ok. fuel pressure is 55. no leak from the intake gasket. this is so frustrating..... FAIL! FUEL PRESSURE SPECIFICATIONS Ignition On, Engine Off Central FI 415 - 455 kPa (60 - 66 psi) SFI 385 - 430 kPa (56 - 62 psi) Edited March 6, 2009 by Removed Quote Link to comment Share on other sites More sharing options...
99ta Posted March 6, 2009 Author Report Share Posted March 6, 2009 I was told by the guy who tested it the range was 55-62, so the pressure at 55 shouldn't cause a miss like that. was I missinformed? Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted March 6, 2009 Report Share Posted March 6, 2009 well i know on the cfi ones that 1 psi will make it run shitty. and which injection system is on your truck? sfi or cfi? Quote Link to comment Share on other sites More sharing options...
Cordell Posted March 6, 2009 Report Share Posted March 6, 2009 wouldn't the cat issues cause a code? prabably not, clogged cats could cause a code like a p0300 if it's bad enough, but usually catalist deficency doesn't go along with clogged cats. I'd look harder at your fuel issue first. Quote Link to comment Share on other sites More sharing options...
99ta Posted March 6, 2009 Author Report Share Posted March 6, 2009 well i know on the cfi ones that 1 psi will make it run shitty. and which injection system is on your truck? sfi or cfi? lol i don't know. its the 5.7 vortech. Quote Link to comment Share on other sites More sharing options...
99ta Posted March 6, 2009 Author Report Share Posted March 6, 2009 ok another question. the fuel pump, should I replace the whole unit or just the pump. big price difference. Quote Link to comment Share on other sites More sharing options...
Awfulcanawful Posted March 7, 2009 Report Share Posted March 7, 2009 I had the same issue with my truck did all the crap you described above to no avail...Ended up pulling out the distributor and the gear was worn razor sharp. I got a new replacement gear from napa and installed it and the miss went away. The only glitch was i had to have a scanner to reset the timing because aparently these engine are pretty picky about where the distributor is set. Hope this helps. Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted March 7, 2009 Report Share Posted March 7, 2009 (edited) I had the same issue with my truck did all the crap you described above to no avail...Ended up pulling out the distributor and the gear was worn razor sharp. I got a new replacement gear from napa and installed it and the miss went away. The only glitch was i had to have a scanner to reset the timing because aparently these engine are pretty picky about where the distributor is set. Hope this helps. come to think about it, i have came across that a few times on those.. you could watch the timing jump around on the scan tool... Edited March 8, 2009 by Removed Quote Link to comment Share on other sites More sharing options...
99ta Posted March 7, 2009 Author Report Share Posted March 7, 2009 thanks for the help. I changed the fuel pump today and I think I fixed it. only dorve it about 10 mins so we will see when i drive it more. thanks for all your help and I will post up for sure when I get to drive it more. Quote Link to comment Share on other sites More sharing options...
99ta Posted March 8, 2009 Author Report Share Posted March 8, 2009 wel... not fixed. pulled the distibutor out and the gear looks worn and the edges are sharp? guess I will change the gear. now what kind of tool do I need to set the timing back? Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted March 8, 2009 Report Share Posted March 8, 2009 need a scan tool to get the timing just right. you have to watch the numbers on the scanner to know where 0 is. you can come close dropping it back in at the mark. did you line it up before you pulled it out? Quote Link to comment Share on other sites More sharing options...
99ta Posted March 9, 2009 Author Report Share Posted March 9, 2009 no, I didn't mark it exactly. I can get it close though... Quote Link to comment Share on other sites More sharing options...
AJ Posted March 9, 2009 Report Share Posted March 9, 2009 you can set the timing by unpluging the timing connector and setting it to what the lable under the hood tells you. just like any other SBC. you can use a scan tool if you need to. Quote Link to comment Share on other sites More sharing options...
99ta Posted March 9, 2009 Author Report Share Posted March 9, 2009 what happens if I put it in way off, will it hurt anything while I adjust it with the scanner? Quote Link to comment Share on other sites More sharing options...
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