Lantresor Posted July 20 Share Posted July 20 Hey guys, about a month ago I bought a 1989 4.0 inline 6 that's 2WD. It sounded and seemed to run well when I test drove it, so I bought it and trailered it home. Once I started driving it around, I noticed the idle sounds worse, like it's stuttering. RPM barely changes, though. It also started to occasionally stall when coming to a stop or accelerating from stopped. I got stuck in road work and every time traffic came to a stop, it'd shut off and I'd have to start it back up. I've done Cruiser's tips 1-5 and so far nothing has made a difference. I did a smoke test in several spots and the only leak I've found so far was at the crankcase breather gasket at the back of the valve cover - I have a new one ordered. I've read that the exhaust manifold commonly breaks at the bottom weld, so I was looking to see if any smoke came out there, but I never saw any. Is there a better way to test this? Also I hear a quiet knocking that doesn't change with RPM, I'm going to get a stethoscope to try and figure out where that's coming from. So far I've replaced: Spark Plugs + Wires Distributor Cap + Rotor ICM + Coil MAP Sensor + its vacuum line Both Vacuum Harnesses O2 Sensor IAC valve Big 7 Wire upgrade I'm pretty new to wrenching and I'd greatly appreciate any help or insight. I love this little truck and hoping to get it to a place I can confidently daily drive it. Link to comment Share on other sites More sharing options...
Ωhm Posted July 20 Share Posted July 20 Cruiser Tip #8 8 – TPS testing and adjusting Link to comment Share on other sites More sharing options...
pizzaman09 Posted July 20 Share Posted July 20 I know you've done the smoke test but did you check to see if your intake/exhaust manifold nuts are tight or if they are even all there? Link to comment Share on other sites More sharing options...
Lantresor Posted July 20 Author Share Posted July 20 1 hour ago, Ωhm said: Cruiser Tip #8 8 – TPS testing and adjusting Thank you, I'll do that next today! 1 hour ago, pizzaman09 said: I know you've done the smoke test but did you check to see if your intake/exhaust manifold nuts are tight or if they are even all there? I checked the top ones, they were tight and all accounted for. Haven't checked the bottom half yet, but I'll do that today and re-snug them all just in case. Link to comment Share on other sites More sharing options...
pizzaman09 Posted July 20 Share Posted July 20 When I purchased my truck they were all loose and the lower back one was missing. It had the same symptoms your truck has. Link to comment Share on other sites More sharing options...
Lantresor Posted July 20 Author Share Posted July 20 2 hours ago, pizzaman09 said: When I purchased my truck they were all loose and the lower back one was missing. It had the same symptoms your truck has. You called it haha, I am missing the bottom back bolt too. Thanks! Link to comment Share on other sites More sharing options...
rokinn Posted July 20 Share Posted July 20 1 hour ago, Lantresor said: You called it haha, I am missing the bottom back bolt too. Thanks! Check to make sure it isn't just broken off with the remaining portion still in the head and not able to be seen. If so, you just went from the minor league to the major league in terms of the job. And if that's the case you are going to need a right angle extension for a drill and a "short" cobalt bit plus an extractor. If you get lucky that will be it. If you're not lucky you'll be pulling the head. Ask me how I know. Try not to bugger the threads on the head or you'll need a helicoil as well. Link to comment Share on other sites More sharing options...
Lantresor Posted July 20 Author Share Posted July 20 Man that's a terrifying thought. I tried to jam my phone in there and get some pictures of it since I can't get a good look myself. It doesn't look, to me, like it's broken in there. What do you think? Couldn't get a great angle still... Link to comment Share on other sites More sharing options...
fiatslug87 Posted July 20 Share Posted July 20 Get a piece of wire and probe it, how far in does it go? Isn’t that one a stud with a nut? Link to comment Share on other sites More sharing options...
Lantresor Posted July 21 Author Share Posted July 21 4 hours ago, fiatslug87 said: Get a piece of wire and probe it, how far in does it go? Isn’t that one a stud with a nut? I wouldn't have thought of that lol. I'll poke one in in the morning, excellent idea. I looked at a diagram and it does look like it's supposed to be a stud Link to comment Share on other sites More sharing options...
fiatslug87 Posted July 21 Share Posted July 21 See the end of this post. Link to comment Share on other sites More sharing options...
pizzaman09 Posted July 21 Share Posted July 21 On mine the stud backed out completely, so I just purchased a grade 8 bolt and threaded it in. Also if the back one is missing, I bet the rest of the lower ones are loose, check to see if they are tight. Link to comment Share on other sites More sharing options...
Lantresor Posted July 21 Author Share Posted July 21 Jammed the wire in there like suggested and it went in about 2-3 inches so I think I'm good to just send another bolt. Hopefully... lol Definitely going to tighten them all again once I have that bolt in. Thanks a bunch guys! Link to comment Share on other sites More sharing options...
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