WHAT NOW? STILL RUNNING ROUGH

  • Tiny
  • goodheart99362
  • Mercury Sable

91 mercury sable/125k/3.8l--after complete tune up still rough, 3 scans gave me diff. Things which I replaced--o2 sensors, heat temp sensor, etc. Checked 4 vacuum leaks, cleaned egr valve, cylinders are EVEN. Changed filters, wires, plugs, pc valve. Ran fuel cleaner thru gas at least 3 times now. Engine light comes on only sometimes but goes out after about 10 sec.I suspect one thing--bad spark plug wires, which would very much upset me-supposed to be lifetime and after all this money and work it turns out THIS? What else COULD it be? Tired of getting ripped off and the results from it--see how it snowballed?

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Thursday, April 12th, 2007 AT 3:16 PM

4 Replies

  • Tiny
  • merlin2021
  • Expert
  • 17,587 posts

On 91's it's usually the manifold absolut pressure sensor. MAP!

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Sunday, April 15th, 2007 AT 8:37 AM
  • Tiny
  • goodheart99362
  • Member

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After reading some of the answers I thought of that, but why didn't that show up on the scans? I don't want to by another part and have the same problem. How can I test for it? It's easier to test the wires--simple things first. I have a manual but it's basically the same thing: "it could be this or this or this". I work on cars myself and maybe that's why they are taking advantage of me (female). Also want to share info for huge savings on parts: PartsAmerica. Com. You look up your part and they send you to a local affiliate, where you get up to or even more than a 50% discount. The site tells you if it's in stock, and the "affiliate" can't jerk you around. Only on a special order--like a custom/import part--can they charge you a regular price. Well thanx for the suggestion. Maybe I'm getting somewhere. Why the fuk did they put computers in cars?

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Monday, April 16th, 2007 AT 1:35 PM
  • Tiny
  • merlin2021
  • Expert
  • 17,587 posts

Yes if you have a code reader it may give you a fault code for the MAP The other thing you can check for is vacuum leaks, get a can of spray gumout, spray around vacuum hoses and intake manifold, see if the engine changes speed. If it does you've found a leak.

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Tuesday, April 17th, 2007 AT 3:57 AM
  • Tiny
  • goodheart99362
  • Member

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I had checked for vacuum leaks but will try the gumout thing. Don't have a code reader--have enuf useless tools! A MAp sensor will cost me about $100-even at a discount price (PartsAmerica) so thanx for the tip. Will keep you updated until I find the problem. This should be a really good engine when I'm done! My last old beater won 2nd in a Demo Derby-it had a V-6 in it too. P.S. Cool name. That was my uncle's name too, only spelled Merlyn. (German)

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Tuesday, April 17th, 2007 AT 1:42 PM

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