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  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

Does this seem like a vaccum leak????

  • Thread starter Thread starter canadianmaple
  • Start date Start date May 28, 2005
C

canadianmaple

New Member
Mar 30, 2005
18
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0
May 28, 2005
#1
  • May 28, 2005
  • #1
Hi guys,

This might be a lengthy explanation as I will try to explain all symptoms.

About a week ago, I started noticing that it would take a few seconds for the RPM's to drop when disengaging the clutch or when shifting gears. The engine would just keep revving then drop to idle. This would not happen when punching it but only when easily accelerating or when slowing down. Around the same time, I started noticing that after starting the car and backing up, when the clutch was pushed in before shifting into first, the car would almost stall for a second before picking up its idle again.

I just drove about 1600 miles in two and a half days with my Mustang and after the first day, I had driven about 650 miles. When I stopped for the night, my car felt like it had lost some power. I used to be able to break the backend loose in second gear but after driving all day, I couldn't spin the tires anymore......not even in first. My second gear which is usually a killer, now felt gutless. I have a Vortech S/C installed running 11 lbs boost with no intercooler and the car had been running all that day at 70-75 mph so I thought maybe that might of had something to do with it. When I got up the following morning and got going again, the whole power issue still didn't seem right. I noticed that when I stopped at a light or something, my idle would climb to about 1300 rpm then drop to about 900 rpm then climb again and so forth. Stopped at a gas station earlier today and as I was leaving, I stopped to let traffic go by and as I pushed in the clutch, the idle slowly kept dropping below 1000 rpm then the car stalled The power in third and fourth gear seem ok....they might be off a little but not like first and second.......it almost seems like the problem occurs in the lower rpm range.

Well I got home today, let the car sit for about 8 hours, just went out to start it and even on startup, the idle fluctuates I do have an autometer vaccum/boost gauge installed. The vaccum reads 20 which is usually what it reads at idle. the needle was moving slightly with the fluctuation in idle but it was so slight that you had to really look closely to see it move........and it didn't move much. It didn't even drop to 19. One thing I did forget to mention is that I didn't really check for boost level but earlier today, it did punch it in third gear and happened to look at boost gauge. I saw the needle at the 10 psi mark at the least.... might have even been 11 psi, I looked quickly. Seems like the boost is holding also so I'm a bit confused here. Could this be vaccum related?
 

RedBullitt

New Member
Jul 7, 2004
462
0
0
Morgantown WV
May 29, 2005
#2
  • May 29, 2005
  • #2
you should be able to hear any major vaccum even when the car is just idling, do you think this could possibly have to do with your maf sensor element? cleaning it with alcohol could help, gently. i dont have much experience with FI, but sea foam works wonders with little engine quirks. Have used it in many, many cars and other engines. Its like 6 dollars at autozone etc. hows your tune?
 
C

canadianmaple

New Member
Mar 30, 2005
18
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0
May 29, 2005
#3
  • May 29, 2005
  • #3
I'm not to worried about the tune. It was done by Lidio at Alternative Auto in Michigan at the man is a God when it comes to SCT tuning.
 
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