af41

I have a 94 5.0 with 108k and I've had problems with it lately cutting out on me. The problem usually occurs when the car is cold. When at a stop or rolling to a stop, the RPMs will surge slightly and the car will stall. Other times, while on the freeway, the car will hickup while cruising. Almost cutting out real quick. I recently changed the spark plugs to regular copper plugs and only gapped them to 50 rather than 54. I thought 54 was alot. Could the problem be that they aren't gapped enough? Initially I thought it might be the fuel pump, TPS, or the alternator(all original). I have a superchip and Granatelli MAF too. Any suggestions?

88GT40

if it was your alt you'd know. you'd be jumping it every morning, i would get some better plugs and gap them right. get a good set of wires too. go from there.

roundman

pull and clean the throttle body and the IAC on the side of the throttle body with some carb cleaner and see if this doesn't fix the problem. your plug gap and type is fine, leave them alone.

88GT40

better yet listen to roundm he's smarter...lol i'm just a newbie

sc94gt

How old are your o2 sensors?

mustang_sally

When my car is doing stuff like that it vapor locks.

Syndicate

I had the same problem with my 94 GT 5.0. It has to do with the ignition side of it. Usually when the rpms are jumping around a little it means that one or more the wires from the distributor isnt working. Replace the wires the same time you replace your plugs. Also check the impedance of the wire from the ignition coil. But it is definately on the ignition side. After i changed the wires plugs and checked everything ignition wise. it ran stock again

All my symptoms were the same as yours. The car would jerk while cruising. and the rpms will be jumping around when the engine is cold.

af41

Thanks for all your help....I replaced the alternator after testing it. I thought that cured the problem, but tonight she was doing it again on the fwy. She wants to cut out while cruising. It scared me so I nursed her home. I cleaned the throttle body like you said roundman, but I guess that wasn't the problem. Syndicate, I think you are on to something. When I changed the plugs, I also changed the wires and cap and rotor. The cap is msd, but the wires are a no name brand. This problem started after I changed them. I used copper plugs rather than platinum cuz some dude at Lincoln motorsports told my bro who has a mark viii that they run their best times on regular copper plugs. Thought I would give them a try. I'll change the wires and see if that helps. Thanks guys.

88GT40

I GOT THIS INFO FROM A TECH SITE ON WWW.PRO-FLOW.COM
THIS WORKED FOR ME
Idle speed set on the throttle plate is too high; usually this error is characterized by a very erratic idle and stalling when coming to a stop.
Set the throttle by removing the connector from the idle speed control motor.
With engine warm and air conditioner turned off, set idle speed at 700 RPM using the throttle screw.
Reconnect idle speed motor and check for engine stability.
Check system for vacuum leaks and fix them.

bmorrisj

make sure the TFI module is being properly cooled and electronic pickup in side the dizzy is still operating correctly...