Smooth power loss when cold - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

carazy · 04-10-2003, 01:07

Hey all a bit annoying thing has been happening with my car so I thought I'd post up here.
When the car is cold is seams to have a flat spot in the rev range where no acceleration is felt.
It doesn't miss or idle ruffly at all and once the car warms up it runs perfectly.
This has been an issue for a couple of months and was getting worse.
I have since changed the following things.
converted to MPFI which changed the fuel pump, all the throttle stuff. (so TPS/MAP sensor/ thottle plus every thing else on the manifold) and the ECU.
I then later changed the dizzy over to a 2 month old MPFI dizzy and changed the throttle body (with ICS and TPS) from the ED i'm wreaking.
The only thing I havn't changed is the coil.
Now I didn't think coils could do this so is there anything else that could cause the problem?
(Plus that damn coil is a bitch to get to so I'm hoping it's something else)

Bass Crazy · 04-10-2003, 02:07

hmmm.. to be honest mate, it sounds to me like the TPS is suspect... since the power loss is smooth, with no surging etc.

I went through 3 S/H units when I put the EF manifold on mine before I found a good one.

Might also wanna check the timing just for the sake of it.

carazy · 04-10-2003, 02:58

the car has had 3 tps units on it and the problem isn't the TPS.
I drove the car that the last TPS came off and there is not problem in that regard.
It's hard to describe how it feels.
I know it's nothing that I said I replaced before or any loose wiring because most everything has been changed when going to MPFI.
Timing is spot on as well.
I'll replace the coil tomorrow and see if that fixes it if not I'll have to start looking at dirty relay connections or something.

carazy · 04-11-2003, 01:17

alright coil was replaced and it still did it.
But thankfully I found the problem.
The red cable powering the ISC was earthing out against the throttle body causing the ISC to open a little to much so the car was running to lean when cold.
I resoldered the connections and now all is sweet.