rough idle

  1. J

    Dies on cold start unless throttle is applied and bogs on initial acceleration

    I am at my wits end, I have replaced near every sensor I can think of on my motor (‘89 5.0) and yet everytime I have to start the car cold it revs up and dies. It will restart immediately and then struggle for a few seconds before dying. Once it finally finds its idle and goes into gear (AOD) it...
  2. A

    2001 Mustang GT - Rough start, rough idle for a few seconds, shuts off and no start after.

    I have a 2001 Mustang GT that turns over and runs very rough for a few seconds and then turns off. When I turn to start it back it will try but will not turn over. After waiting a little while it does the same start for a second rough and cuts off. When I give it gas it try’s to run really rough...
  3. lojo1

    92 LX rough idle and heavy exhaust fumes

    Okay, here I go again (on my own)..... I've recently (1.5 weeks ago) purchased this car, which my father owned up until 2019. The last owner put a cam (303 I think) in it and installed a Magnaflow exhaust (no catalytic convertors). My problem is it runs fine once it gets up to temp but...
    • lojo1
    • Thread
    • 92 fox body mass air flow rough idle strong exhaust fumes tps
    • Replies: 10
    • Forum: Fox 5.0 Mustang Tech
  4. MSTNGGRL1995

    Rough, loping idle and random attempts to die

    Hey guys I've got 1995 5.0 GT. I've had it for 2 years and it's always had a bit of a rough idle, but it's gotten progressively worse. When I say rough idle I mean that when I start it the RPMs rev up to about 1200, then drop to 1000, then drop to about 750. It then proceeds to repeat this...
  5. J

    04 GT New intake manifold and car now has a rough idle

    I'm new here but I have a 04 GT standard trans and my OEM plastic manifold broke at the heater hose fitting so I replaced it with a professional products typhoon intake manifold and I installed it and now the cars idle is very rough. Bouncing between 1200 rpms and 500 rpms. Thought it could be...
  6. P

    Just arrived with a 1965 289 and a 1973 Mach I - and a vacuum leak solved

    I just joined this resource and want to introduce myself. I own a 1965 red convertible 289 with a Holly 4 bbl and a 1973 yellow Mach 1. A couple of days ago I was driving my 1965 and all was well - nice trip around the "long block". A little later my daughter and her friends wanted me to take...
  7. L

    Engine Rough Idle at Start, Possible CMCV Vacuum Leak

    Hi, I have a 2015 salvaged coyote in a 67 mustang running on the control pack. Everything is up and running, but it seems to have a rough idle at start. The idle continues to be rough until I rev the engine and it settles down to normal at around 1000rpm for about 5 seconds, after 5 seconds...
    • larsond12
    • Thread
    • 2015 ford mustang cmcv hanging rpm idle idle issues idle problems rough idle throttle body vacuum vacuum leak
    • Replies: 0
    • Forum: 2015 - 2023 Specific Tech
  8. P

    1995 GT 302 5.0 with rough idle and weird behavior (with video)

    So I recently got this manual 1995 GT with only 44k original miles, the car is great overall. BUT, I couldn't help but notice it has a rough idle (the engine shakes considerably but nothing too crazy) and can't maintain stable RPM's at idle (altough you can barely notice the difference, the...
  9. D

    Engine Vacuum problem

    I’ll make this as short as possible. Basically I plugged off all my unused vacuum ports on the “vacuum tree” and it bogs down like it wants to shut off once it’s warmed up. But it runs good at idle. But if I pull a couple of them off it doesn’t shut off but idles down a lot and runs worse. Any...
  10. H

    Mustang running rough

    Hey guys, I drive a '98 mustang gt convertible, we swapped the motor out for an '03 v8. It has roughly 140,000 miles on the engine. In the past month it has started running real rough and my dad and I can't figure out the problem. When I first crank it and drive it it will be okay for about 10...
  11. I

    96 Mustang V6 Help

    hey I'm new here and was wondering if anyone had a similar problem with their mustang like me. My mustang has been having a hard time starting lately and when it finally does run it idles at 1100 rpm and acts like the chokes on and also idles rough under 1500 rpm. If I give it gas while it's in...
  12. T

    89 5.0l Iac Valve Operation

    Trying to troubleshoot 89 5.0L with rough idle when first started, down to the IAC valve. Pulled this valve and attempted to clean it, but looked clean already. My question is: how much travel does a correctly functioning IAC have? This is a basic two port spool valve but, while the spool in...
  13. PJalbanesi

    Idle Surging

    I have a 1990 GT convertible and the idle was surging after a few minutes of running so I did some research and replaced the IAC valve and when I started the car it ran great for about 10 minutes then it started to surge again so I replaced the TPS sensor as well and adjusted it to about .96 and...
  14. J

    Please Help Can Not Figure Out Electrical Problem

    I just bought a 2003 mustang gt three weeks ago and I have been chasing an electrical gremlin. the person before had spliced in a custom alarm system and I found the tail light fuse was blown. some of the things that I have noticed is when the car warms up the battery light comes on. had the...
  15. D

    1991 Gt Foxbody Rough Idle/stalls

    So my 91 GT has been having some idling issues lately. Whenever I start the car it either stalls straight away if I dont step on the gas right away, or the RPMs will just jump around and it will not stay steady, and the eventually stall out. This past summer I took it on a pretty far road trip...
  16. S

    99 Gt Intermittent Driveability Problems

    Hey guys, New member, i have used this site's knowledge in the past on many issues ( thanks for that), but I've come to a problem I need to reach out to you guys. I am on many different forums, bikes, motorcycles, chevy truck etc.. so let me start by saying thanks for looking at a new post by a...
  17. Amber Midkiff

    Help! Misfiring, Stumbling, Rough Idle, And Loss Of Power

    Merry Christmas my fellow gearheads! I have some major mustang problems and I'm hoping someone can help me, you all always have good advice and I've always had good luck with this forum. So here's the issue. I have a 2001 Mustang GT 4.6 SOHC with 130,000 miles on it. Within the past 4 months I...
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