Just so you know my mechanical skills are some what limited when it comes to cars so i hope you can bare with me... My Bronco seems to be hesitating and im getting a lot of engine vibration. It idles a little rough but does not die. When I go to accelerate like I said it hesitates like im loosing power, gaining it back for a split second and then loosing it again. Seems to smooth out when increasing RPM but can still tell the hesitation is there.. I called my dad (family mech) he said it could be one of three things.. 1. Vacuum 2. Its misfiring 3. Fuel injection. So me being me I went with the easiest that "I" could do with my limited tools and resources and opted to replace the plugs, wires, distributer, and rotor. I would actually be able to tell you if this fixed the issue or not but AutoZone gave me the wrong wire set so I have to go back tomorrow and get the correct one.. But anyway I was wondering if you agree to my dad’s assumption? If it is in fact vacuum, where can i find an accurate and complete diagram and instructions on how to test and troubleshoot vacuum leaks?Also while changing the plugs I noticed that my PCV looks weird. It has two connectors on it. The one on top doesn’t exist it looks like a hose goes there but the hose is not present and I don’t even know where it would go if there was one. The connection on the bottom is there and it leads to the throttle control somewhere.. idk.. like I said lack of mech ability..... So im going to try and replaced the PCV but does something connect to the top portion and where does it go? I hope the little and poorly described info helps you help me lol

 

Ok, so I got the correct plugs and installed them then took it for a little test drive. I went around the block a couple times where the speed limit is 35 and it ran great. Got back to the house turned of the engine and went inside to get rdy for work. Came out, started it up, backed out of the drive way, put it in drive, gave it gas, and Blamo the hesitation is back just like before..... All I did was park it and it went from good to crappy.... Also noticed while it was running good my oil pressure gauge was reading some what in the middle range, but with it hesitating again its so high its almost out of norm... Which was the case before I replaced the plugs.. Someone told me at work to replace the fuel filters so I might go with that and see what happens. It does seem like it could be a fuel problem but it could also be something else.

If anyone could give me advice or tell me somethings to look at it would be greatly appreciated.. This is my only mode of transportation and haveing it crap out on me is a little upsetting if you know what i mean.

 

Probably wasted money on plugs and will do so again sooner than later. Sounds more like a vacuum leak, stopped up catalytic converter, or faults in your engine management system or sensors. Could even have a bad EGR valve. I'm leaning towards EGR and cat converter having issues, though, in your case.

 

No cap on the extra port? I suspect you might have found your first vacuum leak. If you can't find a hose that attaches to that point, cap it off and see if that helps. Towards the rear of the upper intake is a collection of vacuum ports. Make sure each one has a hose or cap on it and make sure those hoses are in good shape.

A couple of other things I might suggest you look at. I might pull codes, especially on an '87 that doesn't have a functional CEL - just to see if the computer is seeing a problem in engine management. I might also check fuel pressure to make sure fuel delivery seems to be up to par.

 

I have the 'dual port' PCV valve on mine, too. It's supposed to be capped off, there is no hose that goes to that on an '87. I didn't even see that until mrshorty pointed that out. That is a definite first thing to correct.