Zero Knievel Posted March 16, 2012 Share Posted March 16, 2012 Not sure what's causing this. It got progressively worse until I tried to take steps to correct it. Basically, if the engine is in lower RPMs and under load (going up a hill) you get that stumbling sensation like it wants to stall. You don't get it on a level surface...that I can reproduce. This is uncharacteristic stumbling...happening at RPMs where it use to never happen. A hill I used to be able to take in 5th gear, I now need 4th. 4th needs 3rd, etc. I replaced the fuel filter presuming the fuel flow was being restricted. It got a little better, but not solved. Replaced the Mass Air Flow sensor. I seems better, but not solved. I did not yet disconnect the battery to reset the ECM...in case "learned" settings are making it happen when it doesn't need to. I have replacement spark plugs...have not yet installed them. I don't have a problem when idling or it's over 2,000 RPM...at least nothing noticeable. 180,000 miles on the odometer. Not sure what else to look into. Quote Link to comment Share on other sites More sharing options...
The Krypt Keeper Posted March 16, 2012 Share Posted March 16, 2012 fuel pump itself?... (do you let it run low fuel level for a while? this kills pumps quick along with Ethanol) all is well while there isn't much work load.. but when you put pressure on the engine and require it to actually work (climbing a grade) it stumbles and hiccups to deliever the amount of fuel. Any check engine lights on or come on during this condition? Autozone and a few other places will scan them for you for free. Fuel pump is in the tank. Should be on driver side, run tank near empty, disconnect the fill hose, and wire and hose on the top. Then should be two straps fun to get too if you got the 20gal tank. My truck is lifted so its easier. or..... open fuel door remove bolts, remove tail lights and disconnect, and tag lights. 6 bolts in bed. Should be big ass star bit. remove these and have a friend help remove the bed from truck. Its not really that heavy. When I lifted my Ranger I had a couple buddies hold the bed up while I placed in the 3 inch body lift blocks. I would remove bed before tank just because its faster and getting to old to be laying on the ground. Then.... you got the fuel injectors themselves.. do you ever run any cleaner in the system? Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted March 16, 2012 Author Share Posted March 16, 2012 1. Fuel pump ... it'd be nice to diagnose it first, but I doubt that can be done. I typically run the tank to E then refill. After 180K miles, who knows. 2. No check engine light. Already ran it by Autozone for a code check...nothing stored. 3. I run B12 Chemtool when I think it's needed. Just ran the second can through. I doubt it's an injector. Quote Link to comment Share on other sites More sharing options...
The Krypt Keeper Posted March 16, 2012 Share Posted March 16, 2012 how long has this been going on? most of the time a fuel pump don't last long once it shows signs of going south. Did have my company truck do this for over 2 yrs as our mechanic and boss didn't find it to be a safety issue.. Running your tank to (E) can allow for your pump to run hot as the fuel itself is used to keep the pump cool. a fuel pump going south will cause surging and stumbling though..so will water in the tank. with days shifting from 20 deg to 70deg for the past month or so could allow condensation to form. or stopping some place with shitty gas. Had this happen to me once also. took a couple tanks to clear it out. but my truck would go from running fine to flat on its face no matter if under load or not. Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted March 16, 2012 Author Share Posted March 16, 2012 how long has this been going on? most of the time a fuel pump don't last long once it shows signs of going south. Did have my company truck do this for over 2 yrs as our mechanic and boss didn't find it to be a safety issue.. Running your tank to (E) can allow for your pump to run hot as the fuel itself is used to keep the pump cool. a fuel pump going south will cause surging and stumbling though..so will water in the tank. with days shifting from 20 deg to 70deg for the past month or so could allow condensation to form. or stopping some place with shitty gas. Had this happen to me once also. took a couple tanks to clear it out. but my truck would go from running fine to flat on its face no matter if under load or not. Maybe the last 2-3 weeks....not much longer than that. Contaminated gas...unlikely. The new pumps are designed to not introduce water/contaminants. Condensation? Maybe. I think other than adding fuel cleaner, the only option is to dump in a bottle or two of rubbing alcohol (what "dry gas" is composed of). Quote Link to comment Share on other sites More sharing options...
The Krypt Keeper Posted March 16, 2012 Share Posted March 16, 2012 You running your tank low so sloshing around what little fuel is left can get the water that might be built up at the bottom of the tank suspended enough to pick it up.. I am still leaning towards fuel pump dying as when you put pressure on it, it chokes and can't take it. Does it do it everytime? Had them dying and were 50/50 on how it wanted to run. Go drive somewhere and floorboard that fucker.. climbing a hill even better and put the engine under a load. try to fill up before 1/8th of tank at least.. on the bright side it will seem to make fillups cheaper for you. Quote Link to comment Share on other sites More sharing options...
Musclecar427 Posted March 16, 2012 Share Posted March 16, 2012 Replace the cat. Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted March 16, 2012 Author Share Posted March 16, 2012 Replace the cat. I presume you mean the catalytic converter? Haven't thought of that. Quote Link to comment Share on other sites More sharing options...
DaveK Posted March 16, 2012 Share Posted March 16, 2012 cap & rotor Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted March 16, 2012 Author Share Posted March 16, 2012 cap & rotor EFI...no cap and rotor. I managed to reproduce the issue on a level surface. Basically put it in 2nd or 3rd gear and push the pedal to the floor. After a few jolts of that, it was less noticeable, but if you can hold out until the engine starts hitting 3,000-4,000 RPM, you get intermittent knocks from the motor when the stumbles happen. This, to me, was new since the few times I manged to rev the engine under load, nothing happened...but I wasn't really trying then either. I'm replacing the spark plugs tomorrow. Past experience always had a failing CC with an odor problem. I'd not expect the engine to run smooth at all if there was a significant exhaust obstruction. Quote Link to comment Share on other sites More sharing options...
blackhawkxx Posted March 16, 2012 Share Posted March 16, 2012 You don't state the year or motor size but I have a Ranger and was having problems that seemed like yours. It surged under load. Putting new Motorcraft plug wires on fixed it. Quote Link to comment Share on other sites More sharing options...
Musclecar427 Posted March 16, 2012 Share Posted March 16, 2012 If the new plugs don't do it here is a test to see if the catalytic converter is faulty. Remove one of the o2 sensors and see if the problem still exists. Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted March 17, 2012 Author Share Posted March 17, 2012 If the new plugs don't do it here is a test to see if the catalytic converter is faulty. Remove one of the o2 sensors and see if the problem still exists. Yeah, if plugs don't do it...next may be plug wires. Are you suggesting removing an O2 sensor (to allow exhaust a different way to vent) or just unplugging it (removing signal from the sensor)? Quote Link to comment Share on other sites More sharing options...
Musclecar427 Posted March 17, 2012 Share Posted March 17, 2012 Exactly, remove the whole sensor to relieve back pressure. It may be hard to tell with the extra loud exhaust but it's a free quick test. Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted March 17, 2012 Author Share Posted March 17, 2012 Well, I definitely need new wires. Tried to do the plugs. Even though I used anti-seize, I can barely turn the first one. Pulled off all the boots and sprayed stuff on each plug to help loosen things up. Might be an all-day job to let that happen. Each time I pulled a boot, dust came out. Inside they each were had a combination of green and white powder. I think it's safe to say that's a big part of the problem. Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted March 19, 2012 Author Share Posted March 19, 2012 Problem solved. Replaced the plugs and wires and all is well. Gonna keep the new MAFS...keep the old one as a spare, but I think the new one makes a difference. Real pisser this weekend was the plugs. Pre-gapped (supposedly) to .050. Motor takes .044. Guy at store didn't say anything, so I presumed they were gapped correctly. For the longest time, as you don't touch the electrodes on the platinum and iridium, my plugs have always come pre-gapped to spec. Since all the plugs seemed shy the .050 they were labeled, I've had no problem (and I don't relish pulling them just to verify the gaps), but to find they now expect you to check and correct single prong platinums really pisses me off because I trusted the manufacturer to have them pre-gapped as marked. Double and quad-prong plugs are non-adjustable. Real annoying. Then I had to go back and get another set of wires because the locking mechanism on the Bosch were too flimsy to stay locked on. Had to get Duralast. Even then, they're saving money by making the wires as short as possible. Fuck. I'll pay the extra $1 or so to have them the proper length. One wire is pretty much taught and unable to go back into the OEM wire guides because it's just long enough to make it. Every wire in the set was about 1-2 inches short of what I pulled off. What really pisses me off is that I had Champion plugs in the truck. Don't recall WHY I bought them (normally not my first choice). Searching my receipts, I did the plugs back in 2004 (Bosch). Did them last in 2009 (Champion). So, I got about 5 years on Bosch platinums and only 3 years from Champion. Auto parts store said the model of my Champions were plain copper plugs, but my receipt says they were platinum. Hmmmmm. Quote Link to comment Share on other sites More sharing options...
tomek Posted March 19, 2012 Share Posted March 19, 2012 Problem solved. R What really pisses me off is that I had Champion plugs in the truck. Don't recall WHY I bought them (normally not my first choice). Searching my receipts, I did the plugs back in 2004 (Bosch). Did them last in 2009 (Champion). So, I got about 5 years on Bosch platinums and only 3 years from Champion. Auto parts store said the model of my Champions were plain copper plugs, but my receipt says they were platinum. Hmmmmm. Well , it is possible someone from government replaced your plugs when you were on motorcycle trip . Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted March 19, 2012 Author Share Posted March 19, 2012 Problem solved. R What really pisses me off is that I had Champion plugs in the truck. Don't recall WHY I bought them (normally not my first choice). Searching my receipts, I did the plugs back in 2004 (Bosch). Did them last in 2009 (Champion). So, I got about 5 years on Bosch platinums and only 3 years from Champion. Auto parts store said the model of my Champions were plain copper plugs, but my receipt says they were platinum. Hmmmmm. Well , it is possible someone from government replaced your plugs when you were on motorcycle trip . While always possible, I wonder if the Champions are just POS plugs or if the inventory was mislabeled. I paid as much for them as I did Bosch platinums, but they didn't last past 3 years. While overall clean, two were really worn down. Quote Link to comment Share on other sites More sharing options...
jon haney Posted March 19, 2012 Share Posted March 19, 2012 I can't be the only one thinking this.................Zero, you need to try another auto parts store. The one you're going to is either hiring complete morons or they are screwing you on purpose. P.S. Take the plug wires back. Every set I've ever bought was longer than stock. Quote Link to comment Share on other sites More sharing options...
blackhawkxx Posted March 19, 2012 Share Posted March 19, 2012 Then I had to go back and get another set of wires because the locking mechanism on the Bosch were too flimsy to stay locked on. Had to get Duralast. Even then, they're saving money by making the wires as short as possible. Fuck. I'll pay the extra $1 or so to have them the proper length. One wire is pretty much taught and unable to go back into the OEM wire guides because it's just long enough to make it. Every wire in the set was about 1-2 inches short of what I pulled off. That is why I said that I replaced mine with Motorcraft wires. Got them from Rock Auto in a couple of days. Quote Link to comment Share on other sites More sharing options...
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