I have a engine miss when Im just cruising, not when Im accelerating. If I accelerate it runs smoothly, its only when Im either just running along at one speed or letting off the gas slowly..I just replaced the egr and the O2 sensor,checked the fuel pressure and checked for vacuam leaks and it still does it..The plugs and wires are only a year old but tomorrow Im changing them hoping that fixes the problem. With it only doing it while going at a steady speed can you think of any other things it might be? Anything you can suggest as being the cause will be appreciated....WW

I cannot be of any help, except to suggest you stop throwing parts at it until you diagnose the problem.

Hopefully someone here with real knowledge will chime in soon.




Good luck!

Im really not throwing parts at it. The egr I replaced had a hole in the diaphram , was leaking air, and not working. The O2 sensor was giving me a high Block Learn reading(148) and a high Integrater reading (132) indicating a possible bad O2 sensor,when I changed the O2 sensor it fixed my Lean fuel problem and brought both readings down near (128) where they belong,as far as changing the plug wires,I already have them so I might as well use them, but I still have the miss when cruising..Thanks..WW

How are the injectors? Maybe one is leaky or something along those lines?

Had a similar problem on a 89 vert. Miss at cruise, full power at WOT. Had one injector that would not seat properly. Two cans of NAPA injection cleaner through the fuel rails solved the problem. This procedure requires specialized equipment.

Suggest reading the plugs when you remove them, if one or more show signs of running rich you may have a similar problem.

Plug wires will likely fix your problem. I had that exact problem on a Ford 302 and it was the plug wires, even though they looked fine. Use lots of wire looms, you need to get it so no wire is touching any other wire or any metal. Sounds impossible but it can be done. Cut to length wires is the best way to go.

I always like to get back and let people know what my outcome was, so maybe it will help the next person with a similar problem..I found out my miss was a short in my coil, the red and white wires touched and burned shorting out and causing a rough idle and a miss at idle and midrange speed....WW

Thanks for that. We do appreciate it!

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+1

Awesome. Glad you found it. Was the miss very noticeable when you were driving? I've got a slight surge at cruise and I've been putting off tracking it down, might be related to the coil like yours.

Matthew

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It was very noticable, it was like a jerking motion as soon as I settled at a moderate speed,I wouldn't call what I had (surging)..There are a lot of things that can cause a car to do this,I was actually checking my distributor cap when I happened to notice the burnt wires,,Purely Luck,,.. Surging can be caused by a EGR valve stuck partially open, IAC sticking or dirty, a vacuam leak is one of the first places to look for surging but it usually does it at idle also.I believe surging is usually a air related problem,but not always..Good luck finding your problem....WW