I realize this is generally a truck type thing around here.. And I do have a few Fords sitting around.
So, here's my problem. I have a 1996 Mercury Cougar. 4.6L V-8. All is stock on it. It seems to me as though the idle rpm's are kind of low. When sitting at a red light, my rpm's are right around 400-500 range. Is this low? Too low?
I ask, because it seems to shutter a little bit here and there like it's running out of gas. It only does it now and then, only when I am a redlight. Will not do it if I shift into park. And when I shift into park, the rpm's go up close to 1k.

This is a new car to me so I am still trying to figure it out as far as how everything acts and reacts.

Thanks for help.

 

It seems odd that the rpm would go up 500 rpm from drive to park. Might be a trans problem but not sure what to check. Try the Thunderbird and Cougar web site.

tccoa.com

Good luck.

 

Is the AC on when you notice this ?

Shut the AC/Heater off completely.

Most engines should idle at 550-650 in drive

 

RPM's will vary for a second when AC is first initiated. Then will level back off.
The AC/Heat has no effect on it at all. It will do it with or without either of those on. It never does die or anything. It just acts like maybe it will. I am going to replace the fuel filter in a day or so because my check engine light is on and that is the only normal maint. item I've not done since owning the car a month ago. That could be it I guess. If not, I will be heading to the shop again. Iwould just rather not go in somewhere and say "it's broke, fix it".

The car runs great other than that. I recently had a new intake put on (due to crack) and had to have the head gaskets replaced and the heads were re-surfaced then. Also, there were 3 burnt valves that were replaced at the same time.
It's just odd because it is strictly a sitting at a redlight thing. I can take off and boil the tires and run it up to 125 with no problem. Does it quick with no engine stumble or miss. Everything is great but that little idle thing.

I will check out the cougar/t-bird site. Thanks.

 

Forget the fuel filter and instead pull the code(s). The check engine light is indicating that there is a fault in the electronic engine management system. Determine what the code is about and address that problem(s). BTW, Autozone pulls codes for free. Make sure that you find out if it's a KOEO (key on engine off), KOER (key on engine running) or a CM (continuous memory) code(s). This is important and will determine which code(s) are addressed first. Hold off on buying any parts from Autozone for now. I would also check for vacuum leaks and make sure they properly hooked up the vacuum hoses when doing the head job.

*A clogged fuel filter causes fuel starvation at high RPM's; since you can "boil the tires and run it up to 125 with no problem" the fuel filter should be just fine.

 

My 85 F150 Flareside (with a fuel-injected 5.0L) I used to have would idle around 500 RPM after it had warmed up.

-Matt

 

Funny how that check engine light just "gets ignored", no?

Come back with the code numbers and we can help you. Since 96 is OBD2 in T-birds, you can't pull them yourself.

Otherwise, don't bother guessing.

 

It's not really that I'm ignoring it. The reason why I haven't figured that into the mix is because the engine light has been on since I got the car a month ago and this problem just suddenly started.


Also, since I'm here.. I was mistaken about the rpm's. When I am sitting a light, they are around 400-500 range. When I put it in park they only jump up to about the 700 range. I said the 1000 range before and I was mistaken.

 

My mom's 2000 Silverado with the 5.3L Vortec idles at around 450 or so in drive. In park or neutral it will hit 550 or 600ish. No effect with A/C. Came to us like that, no problems.

 

There could be a new problem(s) that would cause the CEL to illuminate on top of the prior problem(s) that existed when you bought it and which were tripping the CEL, but until the codes are pulled everything is just speculation.

 

I am going to have pull the codes this weekend and start from there.. I was mainly just looking for some known ideas more than anything.. Because all that "tree huggin" crap gets expensive.

It's times like this that make me wish I'd have went ahead and sank the money paid for the car into my '79F-250. But I guess after I spent all that money, I'd still be left trying to move around traffic in a beast...A beast getting about 8mpg on top of that..But once I get the other '79 sold and the other Cougar sold, I will have some to start working on the F-250..

It all comes out in the wash I guess.