1994 Mustang Gt erratic idle


May 1, 2020
Okay everyone, I'm looking for some help. I have a 94 mustang gt with a 302. It was a manual car and we swapped it to a c4. It has Windsor Jr heads, e303 cam, trick flow intake, K & N CAI, 70mm bbk throttle body, and 24 pound injuctors. I have a couple issues that are stumping us and we're looking for some help. 1. We have an idle issue, it likes to start and die, it acts like it is constantly searching for a signal. 2. It has a ton of blow by, i actually took it to the track for the first time and it literally blew the oil dipstick right out of the tube and blew oil all over. And 3. It likes to get really warm really fast, it can idle for 10 minutes or so and be close to 190+. Any insight would be greatly appreciated. Thank you.
  • Sponsors(?)


I think they're a little easier to get off
May 15, 2018
Well the car getting up to temp quickly is by design. The electric fan doesn’t cut on till the car gets up to temp, so if it levels off at 190* then it’s doin it’s job.

You have to either get the car tuned, or buy a quarterhorse setup and learn the system. I’d recommend having a reputable shop do it, then maybe you can learn some along the way.

Bottom line is the car isn’t going to be very happy with the changes you’ve made without compensating for it in the computer.

For the blow by: is there a pcv? Is it clogged? Lots of blow by can be indicative of ring seal issues. I’d buy a vacuum gauge at the Parts house and see what the gauge is doing. They are great diagnostic tools.
  • Like
Reactions: revhead347