Rough running (almost stall) when cold in Park - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

redtarga · 10-06-2005, 10:57

I'm new to the group, so please forgive me if my question sounds naive. My mechanical experiece is primarily with Porsche and VW, but I did spend several years in the shop of an Oldsmobile dealer. Quite a few of my friends and neighbors now own Ford products, and I must admit Ford is my favorite American make. I'm often presented with questions and requests for mechanical help--and that's the reason for this message. My neighbor called me yesterday to say that he's experiencing a problem with his 1991 Taurus. According to him, the car, when cold, runs roughly and almost stalls in [B]PARK. Move the lever to DRIVE, however, and he says it all becomes smooth again. Move the lever to PARK, and once again the car runs roughly. This scenario contines until the engine is thoroughly warm. At that point engine running is normal in all quandrant selections including PARK. What the....could be causing this? Is there any vacuum device that could be leaking under the described circumstances? Any suggestions would be welcome before I dig in on a wild goose chase. Thanks.

LEWAT · 10-18-2005, 01:38

The Air Bypass Solenoid On Top Of Throttle Body-remove-clean Throughly-with Choke Cleaner-make Sure Spring Moves Freely-reinstall-see If That Solves Your Problem

j9f · 10-20-2005, 05:53

Quote:

Originally Posted by LEWAT

The Air Bypass Solenoid On Top Of Throttle Body-remove-clean Throughly-with Choke Cleaner-make Sure Spring Moves Freely-reinstall-see If That Solves Your Problem

I have the same exact problem. I bought a new idle air bypass valve yesterday. The problem didn't go away.

After 15 seconds or so after start-up, a valve is thrown and the engine drops in RPM. At cold start, it stalls. If warm, the engine can pull through this event and returns to a smooth idle.

I know the valve is doing something because the engine stalls out completely if I remove the wire harness from the valve.

I am wondering if it is the relay.

Gary1234 · 10-20-2005, 08:51

Have you tried reading the trouble codes to see if any problems are stored in the computer? It's easy to read the codes on a '91 .. just takes one jumper wire.

sebastian · 04-08-2006, 18:13

my 93 taurus does the same thing i changed the throttle position sensor no help

sebastian · 04-08-2006, 18:15

Can,t analyize because there are no codes given I have access to a scanner no help