[threeravyn]

I have a 2001 GT convert. with about 45k miles on it. The past 2 months I've been having problems with it while the a/c is on.
After driving it 20-30 minutes with the a/c on the RPM's roll between 700-400 rpm's while at a stop. It starts slowly and builds. The longer I sit there the more pronounced the surge. Twice it's gotten down to 250 then it stalls on me.
I've tried different gas (you never know...), cleaning the MAF, IAC, etc. I even took it took a shop by my house after it died the first time and he ran diagnostics. Nothing came up.
The temp gauge doesn't move, no check engine light, nothing but the RPM's.
I also noticed when the a/c is on and I go from park into gear or vice versa it really surges and takes it a few to stabilize.
My baby is in the dealer service dept right now. And wouldn't you guess it, they haven't noticed a surge. I even went down and drove it around for awhile and got it to do a slight rolling for me, but not for them!
What could be sucking that much energy to cause this? Would a bad a/c compressor do it? Or is my car taunting me?

[90GT AOD]

It's possible the A/C compressor is going bad and dragging your engine down, if it doesn't do it with the A/C shut off, that would be the first thing I'd look at.

[threeravyn]

That's what I was thinking, but the service manager is ignoring me. I asked if that was the problem and he said 'no, it's probably just bad gas.' After 2 months and filling up at different gas stations I really doubt that. Plus it'd be acting up without a/c on. I think he was just trying to scam me for $$$ and get rid of me.
The bad part is because they can't find anything they want to charge me $270 for diagnostics!
I am beyond unhappy with the dealer I took my car to.
I plan on picking my car up and going to a different dealer tomorrow. Like I should've done in the first place.

[90GT AOD]

Why go at any dealer? I worked for 2 dealerships (Ford and Pontiac), and I can tell you first hand that no mechanic at the dealership is any better than mechanics you'll find at a good local shop. The only difference is that the dealer guys get service bullitens and the latest shop manuals, but only one or two guys out of 15 really keep up on the latest material, and your lucky if you get them to work on your car.

[threeravyn]

I tried taking it to a little local shop by my house, but he had no idea what was wrong. I was also expecting it to be covered by warranty. When you're a starving college student car repairs can be a bit much.
Sadly my car is at the dealer right now. I just called Ford's customer service to fight with the $270 for diagnostics.
It's an horrible feeling knowing something is wrong with my car but not being able to prove it.

[threeravyn]

Would the compressor give a code or show up on diagnostics?

[90GT AOD]

Originally Posted by threeravyn

Would the compressor give a code or show up on diagnostics?

No, the only possible code you might get would be if the air controller wasn't working properly, but you would know something is wrong because the air wouldn't be blowing out of the vents properly.

I feel for you, dealerships are a huge rip off because they don't get paid much, if any, labor for warrenty repairs from the company, so they need to make up for the lost labor charges somewhere. Plus the amount of money they make on new car sales alone isn't enough to support a huge facility like most are now.

Another problem with dealerships is that they have a huge turn over in the service department, so no one is really ever familier with your car, like a local shop might be. I'm speaking from a personal experiance from many years ago, so it could have changed, but I doubt it.

[threeravyn]

I might ask them to take a look at the compressor then. I don't expect the mechanic there to go above and beyond trying to find the problem, so he might not have seen it.
Once this is over I plan on shopping around for a new auto mechanic. My warranty gives out in October so after that there's not much reason to go to Ford anymore.
I was also wondering if it might need a tune up. This may be a stupid question, but what do they do for a tune up?

[90GT AOD]

I didn't realise your car was under warrenty, so that explains a lot because most dealers try to spend as little of time as possible on warrenty work, so they will alway over look things and say it's "okay".

Tune ups are basically just spark plugs and new wires (if you even have plug wires) and air filter, your owners manual should point out what needs to be replaced and when.

The saying "tune up" is such an old saying because there's really no tuning of the car because the computer handles everything now. From the early 1980's and earlier, cars needed adjustments on the timing and carbuator, and had a lot of igintion parts that wore out and needed replaced like cap, rotor, points, wires, plugs. So cars would start to run bad after 20,000 miles and need to be re-adjusted or "tuned up".

IMO the saying "tune up" should be renamed to "engine maintenance" because if the car is running poorly, 95% of the time it's going to be a engine management problem that needs to be diagnoised through the computer, which isn't going to be fixed doing a tune up.

[threeravyn]

Ahhh, that explains a lot. So it's stuff that can be done at home.
I'm about to call them and tell them I want a copy of my diagnostics and service because I'm getting a second opinion. For $270 I should get something outta it.

[90GT AOD]

If the car is under warrenty, why do you have to pay $270? That's not right, but I've seen it happen, so what you need to do is be firm with the service manager but don't loose your cool. When you pick up the car have him go for a ride with you, and show him the problem, and point out that the problem hasn't been corrected, that they've wasted a lot of your time and you refuse to pay $270 for them basically doing nothing.

If he refuses to let the charge go, then drive him 20 miles out of the way and drop him off there. j/k

[threeravyn]

I wouldn't mind dropping this service manager off in the middle of nowhere. He's kind of a jerk.
I just talked to my service writer. She said the manager was wrong and I only have to pay $90 for the diagnostics. Apparently the manager is a moron. The $270 is if they found nothing wrong with my transmission or hydroboost (the other things it was taken in for).
If the manager had just said so I wouldn't have been so stressed yesterday.
She also said that they can't recreate the problem. I tried to for them and it wasn't doing it. But if it does it within the next 3 months they'll refund my $90.
Does a compressor slowly go out? I hadn't used the a/c for 3 weeks because of it's stalling, is it possible that kept it from getting worse?

[90GT AOD]

Compressors can go quickly or go very slowly.

The only other thing I can think of is the idle control could be giving you a problem, it basically steps up the idle a bit to compinsate for the A/C drag at idle. I'm just not familier enough with your car to make a educated judgement, but it is strange that it only happens when the A/C is on.

Hope you get it straightend out.

[threeravyn]

Thanks for the help. At least now I have 2 things I can look into. I'll probably figure it out long before the dealer does.
Thank you for all your help!

[ronjon88]

My air revs down and up also as the compressor turns on and off. What i did to fix the problem was recharge the air conditioning and clean the IAC (Idle Air Control Valve) and now it doesnt do it as badly as it used to. I would try that if you havent already. Your cost would be about $30 for both the refrigerant and the Mass Air Sensor cleaner at a local auto parts store. I hope you figure out the problem before the weather heats up.