FLETCH14519 Posted December 6, 2016 Share Posted December 6, 2016 I am a recent owner of a 1987, 2wd, 4.0, MJ. The truck has 82,000 Miles on her, and I have noticed when I run around 65-75MPH the truck gets a slight jerking feeling. Almost feeling like a misfire on the engine, but not. It seems to mainly do it at high speeds, low rpm while going up a hill, or putting alil more strain on the engine. Now I have noticed if I give it some gas, the truck doesn't really jolt, only if I gradually hit the gas and ease into it at high speeds. Here is a list of things I replaced when I bought the truck.... - NEW PLUGS - NEW WIRES - DISTRIBUTER CAP - ROTOR - AIR FILTER - CLEANED THROTTLE BODY - CHANGED OIL AND FILTER Link to comment Share on other sites More sharing options...
cruiser54 Posted December 6, 2016 Share Posted December 6, 2016 Go to my website and do Tips 1 through 5 to begin with. Link to comment Share on other sites More sharing options...
FLETCH14519 Posted December 6, 2016 Author Share Posted December 6, 2016 Go to my website and do Tips 1 through 5 to begin with. Awesome write up, I will go through and check these items this week/weekend. Thanks for the quick response Link to comment Share on other sites More sharing options...
cruiser54 Posted December 6, 2016 Share Posted December 6, 2016 Go to my website and do Tips 1 through 5 to begin with. Awesome write up, I will go through and check these items this week/weekend. Thanks for the quick response You bet. Enjoy. Link to comment Share on other sites More sharing options...
Eagle Posted December 6, 2016 Share Posted December 6, 2016 Check your spark plug wires. If they are the originals, the insulation may have broken down and they may be losing spark energy to any metal they pass near. When this happens, it feels like a misfire -- mostly because it is a misfire. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 6, 2016 Share Posted December 6, 2016 Check your spark plug wires. If they are the originals, the insulation may have broken down and they may be losing spark energy to any metal they pass near. When this happens, it feels like a misfire -- mostly because it is a misfire. He replaced them. Does act like a secondary ignition issue though. Link to comment Share on other sites More sharing options...
Eagle Posted December 7, 2016 Share Posted December 7, 2016 Check your spark plug wires. If they are the originals, the insulation may have broken down and they may be losing spark energy to any metal they pass near. When this happens, it feels like a misfire -- mostly because it is a misfire. He replaced them. Does act like a secondary ignition issue though. Sorry -- I missed that. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 7, 2016 Share Posted December 7, 2016 Check your spark plug wires. If they are the originals, the insulation may have broken down and they may be losing spark energy to any metal they pass near. When this happens, it feels like a misfire -- mostly because it is a misfire. He replaced them. Does act like a secondary ignition issue though. Sorry -- I missed that. Yeah, but the symptoms mimic that..... Link to comment Share on other sites More sharing options...
SVPete Posted December 8, 2016 Share Posted December 8, 2016 Hmmmm, sounds like that "bucking" thing. Ahh, I do remember the first time I felt it, rolling down I-10 at 75 mph with my son (maybe 2005-ish?)....and we looked at one another with the "what the hell was that" look. Hard to believe, 1987 with only 82k? I hit that around 1998 and that was with the truck sitting about three years while I was in Germany. After you work through Cruisers tips....please check back in because coil and EGR come to my mind, but not with only 82,000 miles. Meaning, don't buy parts first. Do the simple and tedious things since they may cure your problem (and they need to be done since they will solve/fix/help so many little things). 29 years is still 29 years, things corrode, gunk hardens, stuff leaks. Link to comment Share on other sites More sharing options...
FLETCH14519 Posted December 8, 2016 Author Share Posted December 8, 2016 Hmmmm, sounds like that "bucking" thing. Ahh, I do remember the first time I felt it, rolling down I-10 at 75 mph with my son (maybe 2005-ish?)....and we looked at one another with the "what the hell was that" look. Hard to believe, 1987 with only 82k? I hit that around 1998 and that was with the truck sitting about three years while I was in Germany. After you work through Cruisers tips....please check back in because coil and EGR come to my mind, but not with only 82,000 miles. Meaning, don't buy parts first. Do the simple and tedious things since they may cure your problem (and they need to be done since they will solve/fix/help so many little things). 29 years is still 29 years, things corrode, gunk hardens, stuff leaks. Lol yes sir. 82,000 miles, no rust, solid all around. Just purchased it about a month ago. So getting the hang of this MJ thing. Link to comment Share on other sites More sharing options...
Tex06 Posted December 8, 2016 Share Posted December 8, 2016 Oh boy, hope you find the issue. My 92 started that way and after months of troubleshooting (problem was intermittent and sometimes left the truck undriveable) it turned out to be a bad electrical connection. Sent from my SM-G930T using Tapatalk Link to comment Share on other sites More sharing options...
Lemmon714 Posted December 9, 2016 Share Posted December 9, 2016 I have an 87 with a 4.0. I had the same issue years ago. My issue turned out to be a cracked sense tube from the throttle body to the MAP sensor. My temporary fix was to heat shrink the cracked tube. I purchased a new tube from the dealer and the problem was solved. I can only hope it would be this simple for you. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 9, 2016 Share Posted December 9, 2016 I have an 87 with a 4.0. I had the same issue years ago. My issue turned out to be a cracked sense tube from the throttle body to the MAP sensor. My temporary fix was to heat shrink the cracked tube. I purchased a new tube from the dealer and the problem was solved. I can only hope it would be this simple for you. Those tubes are no longer available. Here's an alternative fix. http://cruiser54.com/?p=280 Link to comment Share on other sites More sharing options...
FLETCH14519 Posted December 19, 2016 Author Share Posted December 19, 2016 Is there supposed to be something connected here on the connector stem or no? Nothing was hooked up once I removed it Link to comment Share on other sites More sharing options...
cruiser54 Posted December 19, 2016 Share Posted December 19, 2016 No. Link to comment Share on other sites More sharing options...
FLETCH14519 Posted December 20, 2016 Author Share Posted December 20, 2016 No. Ok, I have a few more pictures I'm downloading to make sure all is normal Link to comment Share on other sites More sharing options...
FLETCH14519 Posted December 20, 2016 Author Share Posted December 20, 2016 Is there anything that needs to be hooked up here? I only ask because I found this line just hanging in the engine bay near it, with a plug in it. Which connects here Link to comment Share on other sites More sharing options...
cruiser54 Posted December 20, 2016 Share Posted December 20, 2016 Looks like someone unplugged the EGR valve and plugged it's hose. This help? Link to comment Share on other sites More sharing options...
FLETCH14519 Posted December 20, 2016 Author Share Posted December 20, 2016 Looks like someone unplugged the EGR valve and plugged it's hose. This help? That print out is great. Thank you. Why would you think they would do that at curiosity? Shouldn't that be connected? Link to comment Share on other sites More sharing options...
cruiser54 Posted December 20, 2016 Share Posted December 20, 2016 And this: http://cruiser54.com/?p=121 Link to comment Share on other sites More sharing options...
cruiser54 Posted December 20, 2016 Share Posted December 20, 2016 Looks like someone unplugged the EGR valve and plugged it's hose. This help? That print out is great. Thank you. Why would you think they would do that at curiosity? Shouldn't that be connected? Always remember this: Genius has it's limits, but stupidity knows no bounds..... Link to comment Share on other sites More sharing options...
FLETCH14519 Posted December 20, 2016 Author Share Posted December 20, 2016 Looks like someone unplugged the EGR valve and plugged it's hose. This help? That print out is great. Thank you. Why would you think they would do that at curiosity? Shouldn't that be connected? Always remember this: Genius has it's limits, but stupidity knows no bounds..... So is it possible this jolting is due to the hose not being hooked up to the EGR valve Link to comment Share on other sites More sharing options...
cruiser54 Posted December 20, 2016 Share Posted December 20, 2016 Not likely. Link to comment Share on other sites More sharing options...
FLETCH14519 Posted December 20, 2016 Author Share Posted December 20, 2016 I did do the C101 Elimination. Soldered wire connections than put heat shrink tube over, taped up, and will get wire loom tomorrow. But I am Just slowly going over your steps. Sorry for all the questions. Just trying to make sure I don't miss something. As always I appreciate all the help Link to comment Share on other sites More sharing options...
cruiser54 Posted December 20, 2016 Share Posted December 20, 2016 The Tips are there to be used as a foundation. Do them first. Link to comment Share on other sites More sharing options...
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