aerosys Posted February 8, 2014 Report Share Posted February 8, 2014 Hi guys, I recently (about 5 months ago roughly) had a catalytic converter get clogged on me. I replaced it and ever since I've replaced it, there has been this random non rythmic shutter that happens when I'm idling. Pretty much a rough idle. After my converter went out I replaced the converter then experienced this "rough idle." I replaced the spark plugs, wires and even cleaned the throttle and no luck. Still does it. It isn't horrible and is only noticeable at idle. Sometimes I'll ask my buddies riding with me if they notice it and sometimes they can't when I can which lets you know how mild it is. Mild, but still gets to me because it shouldn't do it. I've also noticed I get worse mileage now. Use to get like 14 city now I can barely get 12.5 if I'm trying to drive it for mpgs. I have true dual exhausts with two cats (1 newer than the other). Was wondering if you guys had any suggestions as to what my problem is. Thanks in advance guys! Quote Link to comment Share on other sites More sharing options...
BlueAWDSS Posted February 8, 2014 Report Share Posted February 8, 2014 You have all the oxygen sensors? Sent from my PantechP8010 using Tapatalk 2 Quote Link to comment Share on other sites More sharing options...
aerosys Posted February 8, 2014 Author Report Share Posted February 8, 2014 Yeah, no check engine light is on either. Quote Link to comment Share on other sites More sharing options...
Blown 346 Posted February 8, 2014 Report Share Posted February 8, 2014 What plugs did you use, and what are they gapped at? Are you sure the other cat isnt on its way out? Or was that replaced at some point? Have you replaced the fuel filter? They only last about a year. I would start by running some sea foam in the gas tank and then add some to the brak booster line. That will clean out all the carbon in the motor, stabilize and clean the fuel system, remove moisture from the gas. Quote Link to comment Share on other sites More sharing options...
aerosys Posted February 8, 2014 Author Report Share Posted February 8, 2014 (edited) Plugs are gapped at .55 and they're ngk v-power. And I replaced the fuel filter a week after I got the truck just so I'd know for sure that it was replaced recently. I'll seafoam the truck in the morning and the other cat very well may be. I'll record temps before and after cat and report back. Edited February 8, 2014 by aerosys (see edit history) Quote Link to comment Share on other sites More sharing options...
aerosys Posted February 12, 2014 Author Report Share Posted February 12, 2014 I dropped the truck off at a trusted mechanic considering they have tons more tools that can test parts and find the issue in a fraction of the time. Plus, they always call before spending any money so I could just tell them I want to "fix" the issue later and take matters into my own hands. I'm just dying to figure out what the issue is and don't have time within the weekdays to do so and would really like to not be frustrated with the truck all weekend. And I've already done all I can really do maintenence wise. Spark plugs, wires, clean and re-oil my air filter, cleaned the throttle body, sea-foam treatment, and fuel filter. I'm hoping it's the old converter or a bad sensor. I really don't hope they come back with, "it's just your engine." Pretty sure I'd cry. Haha! I'll let you guys know the culprit whenever I find out myself. Quote Link to comment Share on other sites More sharing options...
southsidemex23 Posted February 12, 2014 Report Share Posted February 12, 2014 This is crazy! I have the exact something going on with mine! No joke! I replaced a cat last week and it idles a little rough. I'm throwing it on the scanner tonight and check my fuel trims. Also going to clean my MAF. I hope it's that! Quote Link to comment Share on other sites More sharing options...
aerosys Posted February 15, 2014 Author Report Share Posted February 15, 2014 Got the truck back. They said the drop in K&N filter is what's doing it. It's giving more air flow which is making my computer try and compensate for the extra flow so it "shudders" whenever it does it. Told me that would also explain the bad gas mileage considering it's having to spit out extra fuel to compensate. They said my MAF was reading a tiny bit higher than normal, so they replaced it with a brand new one and it still had the same reading. They checked for vacuum leaks and did a all around check-up. In their opinion everything is as smooth as can be to them. They said they think I'm just being a little paranoid about my baby. Haha! I guess it may have idled like that before and I just didn't notice it considering I just got the truck and didn't really have a "feel" for it yet. Eventually I will replace the other cat and for some odd reason despite everything, IF that fixes it, I'll report back, but that's a ways down the road. I'm ordering a tune from Zippy and the mechanic told me that a good tune would actually probably correct it, but he still said he's had brand new truck come in just for an oil change and their idle is perfect and still more rough than mine. Said I was chasing a ghost problem and that I'm just not use to a sportier idle. I also was talking to my buddy with a Ford Lightning yesterday and we were sitting in his truck talking and I noticed his idle feels even jumpier than mine, but he said that's how pretty much all sport trucks idle. The truck runs like a dream too, so maybe is was me just not use to this SS power. Haha! Thanks for all the help guys! Quote Link to comment Share on other sites More sharing options...
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