[86-5.0]

Hello everyone, hopefully someone can shed some light on my issues.. Car will run fine, but as soon as a load is put on the car I lose any kind of power, car will not stall, but it will backfire sputter and hesitate no matter how much throttle (easing into it, or mashing it) there is very little response. I swaped out the TPS, I have no residual pressure at the Schrader valve on the fuel rail with the vehicle off.. I am just trying to figure out which gremlin to chase, Ignition or fuel... any help would be greatly appreciated

[Kyle F]

You should have some residual pressure in your fuel lines when you shut the car off.

Try this... put your fuel pressure gage on the shrader and kick the ignition on, but do not start the car. The Fuel pump will kick on, pressure up the injectors and make their start up fire. So, at that point you should have pressure on the rail. Leave the key in the on position for a minute or two and see if your pressure has a significant drop. If it does you have fuel issues.
1. Injector O-ring seal is leaking and not enough fuel is getting into the engine and running very lean under load.
2. You have a stuck open injector or two and they are just dumping fuel in and not atomizing it so its not burning
3. You could have a weak fuel pump if its never achieving good pressure.

Report these results and we will go from there... at least that is my recommendation at this point.

[coolwaterblvd]

Yea check out your fuel pump also change out your fuel filter first. But most of these problems are fuel delivery and or pump related.

[86-5.0]

what about the pressure regulator? any quick tests for this?

[lxarlo]

Originally Posted by 86-5.0

what about the pressure regulator? any quick tests for this?

if the regulator was stuck full open or had a torn diaphragm, you would sputter and emit a bunch of black smoke. it could be stuck in the minimum fuel pressure but i dont think it would cause what you describe, at least not to the degree you describe. like coolwaterblvd said, its likely in the fuel pump and filter. possibly clogged filter took out fuel pump. get a gauge on there. with vacuum line off regulator, it should read 39-40 psi. 30 with it on. fuel pressure should rise when you accelerate.

[86-5.0]

I am going to put the gauge on monday, left the car at work.
I just put a new fuel filter on it 2 weeks ago when I put hte new motor in. Maybe a bit more info will help a little. This problem happened suddenly while on the highway, but it started with the loss of power, then after driving a bit more the backfireing started it seems to be getting gradually worse... Could it be a bad load of fuel, I filled it up two days ago.........Thanks everyone for all the help, i'll report my progress.

[Kyle F]

IT very well could be a bad load of fuel causing your engine to run poorly, I am more concerned witht he fact that you have no residual pressure in your fuel rails. I am pretty sure there should be some.

[86-5.0]

thanks guys, put a new pump in it today, the rubber line between the pump and the pickup tube had come apart. now we are blasten all the way! thanks for the help.

[sheba]

My 86 has been doing this and getting worst until it got to the point where it would cut off and I took it to the ford dealership where they said I need a new distributor and I read somewhere if your distributor is not putting out a good spark it will lose power at high rpms so I'going to go that route and upgrade to and msd distributor and coil so I'll let you know if that fixes it.

[sheba]

Mine was doing this so I got fed up cause I could not find the answer so I took it to a trusted mechanic that also builds mustangs and he said it sounds like I need new cats even though he suggested off road pipes so he took a cat gun and tested them and sure enough m cats were clogged and needed to be replaced. here is another way you maybe able to tell is engine compartment seem alil excessively hot it's from back flow. but anyway that should fix your problem.