surging idle

  1. M

    Intermittent startup surging

    Few months ago I installed a mspnp2, along with GT40P heads and intake on my 95gt, idling has always been an issue but the startup creeps to around 3k and hangs there for 4-5 seconds before dropping down, this is only when the car has ran in the last couple hours, cold starts in the morning...
  2. 93CalypsoConvert

    Engine Surge on High Idle Only.

    When I start the car, it surges on high idle only. Normal idle and driving is fine. Its a 1986 with a carb set up. Any ideas why it might be surging? I checked for vacuum leaks but couldn't find any issues. I've adjusted my carb and timing where it runs the best. Bad idle circuit maybe?
  3. D

    Surging idle 95 mustang gt 5.0 bolt ons

    I have a 95 mustang gt 5.0 with stock bottom end, gt40p heads 1.6 roller rockers, comp xe264hr cam, 75mm throttle body, 30 lb injectors, MAF calibrated for the injectors, BBK cold air intake, Trick flow upper and lower, pacesetter long tube headers, custom 3” exhaust, no o2s (yet, bought without...
  4. S

    Idle problem 1990 with gt40 crate engine

    Started as a surging idle when the engine warmed up then after a year the idle rose to 2500-3000 rpm I replaced the IAC and now the idle is poor and the car stalls and check engine light is coming on. Thinking about tps next unless anyone can think of something else. I have never had any other...
  5. 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...
  6. D

    Electrical Isolate Starting System And Engine Sensor Circuits?

    Fellas, I've been chasing a No Spark/Surging Idle/Stall, Buck, Backfire problem for quite some time now. I have worked though most of the tech notes I've found on the online, studied the systems using the Helm manuals, as well as the diagrams by jrichker, tmoss & joel5.0, and Tom Cloud's...