rough idle first 30 seconds 97 ford thunderbird 3.8L

Asked by Feb 23, 2017 at 03:49 PM about the 1997 Ford Thunderbird LX

Question type: Maintenance & Repair

So I have replaced spark plugs and wires and air
filter. Very rough starts when it has been driven
then sets for less than half hour to hour. Haven't
had problem when cold starting yet. Could pcv
valve,air sensor,or air intake control effect this. I
also read that maybe a fuel pump relay but in my
car the fuel pump relay is much different then I
read or seen online. Please help I rather fix myself
if I can.

11 Answers


So yes, in the air intake system there is a Mass Air Flow Sensor that you can clean. Make sure you use a MAF spray cleaner.

1 of 1 people found this helpful.

Thanks Rowefast. I just cleaned the mass air flow sensor after posting this. I also had a bad battery replaced and same issues. I tossed some sea foam fuel system cleaner to see if it would help. I have a ignition coil needs installed later today. If that doesn't stop it does anyone have any other ideas?. Could fuel filter, intake air control valve, or some type of regulator be the cause. It really feels like there isn't enough fuel or air on start up but only when vehicle is warm. Thanks everyone.


I looked for a Air Idle Control Valve but there is not one that I could find. Cleaning the throttle body helps also, and yes, change out the fuel filter. If there is an issue yet after taking care of these things, then there could be a fuel issue. Fuel pressure tests would need to be done to pinpoint the problem. There is of course the fuel pump, fuel regulator, and a fuel injection pressure dampener to investigate.

1 of 1 people found this helpful.

Great thanks again Rowefast. I will look into and attempt all that you listed. Is there a specific way I should be cleaning g the throttle body? Thought about doing it before but I didn't want to use something that makes things worse. Thanks very much again.


Gumout Carburetor Cleaner for the throttle body, but make sure and use Mass Air Flow spray cleaner on the MAF. Do not use the carburetor cleaner on it.

1 of 1 people found this helpful.

Thanks a lot Rowefast. If I have any issues after all you recommended I may have to toss towel in here as fixing it is starting to cost more than it is worth. Been a great help Rowefast thanks for your time.


Your welcome.


I think Rowefast has given you about all the most probable cures. Go with all his suggestions.

1 of 1 people found this helpful.

Unhook the vacuum line from the fuel pressure regulator and plug it leaving the regulator unhooked and that will fix the problem. A new regulator didnt work this was the only way i could resolve the problem. What's happening is the fuel that stays in the fuel rail and injectors gets too hot after sitting under the hood and doesnt burn right and makes the car miss and run lean. Unhooking the regulator adds 8 to 10lbs of fuel pressure and thats enough to flush out the hot gas and bring fresh up from the tank. Turning the key on and off several times and letting the pump kick on and off will do the same but this seemed like less of a hassle to do. The car will compensate and keep from running too rich and no check engine lights come on so this is a very easy and permanent fix.

1 of 1 people found this helpful.

Thanks alot Erie... I had a feeling it was something to do with fuel sitting or not getting there fast enough but everything in the fuel system checks out great so this sounds like a very possible fix for me and one that the money pit shops failed to mention. Thanks again. Will try asap


I hope it works for you, we had ours at a ford dealership and they tested everything and it passed and they had no idea what it could be. I actually found that solution from someone having the same issue with a supercharged thunderbird and it made sense the way they explained it so i tried and it worked.

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