I just have a couple of questions on basic engine tuning(some performance), including some problems that Im having with my bird. Maybe its getting too old or maybe I just need to adjust some things, so I will ask you experts and see what you guys recommend...maybe this thread will also be helpful for some out there that are having similar problems

Engine: 2.8 MPFI 60 Deg V6 (173)
Mileage: ~201K(close to retirement?)

Idle:
I cleaned up the fuel system using those off the shelf fuel injection system cleaners. It turned out to be of some help. Before that, my idle wasn't good. It was kinda choppy and wouldn't idle at a constant rpm. Now, it does idle constantly. The only problem is that from time to time it idles around 2000 rpm when in park, in drive it idles around 1100, which to my knowledge is still high. Last time it did that I adjusted the tps and that solved the problem. I will attempt to measure the voltage this weekend and see if that is causing the problem. If that doesn't turn out to be the problem, what else could it be? will also be replacing the fuel filter.

Tuneup:
What do you guys recommend on replacing or adjusting for throttle response? I am getting poor gas mileage so I am going to do a full tune up within the next couple of months and see if that helps. The car has not been as it used to. I would at least get 26 mpg on the highway, now I don't think I even get 20. Any recommendations on spark plugs/wires, etc.?
I've seen Jaspers Throttle response enhancer. Do you guys have any opinion on that?

How would a new timing chain help? I have seriously thought of that considering the mileage on the car.

Leak:
Does a manifold leak cause performance problems? Im going to have a new gasket in next week, it is definitely annoying.

Transmission:
It seems to shift to soon. It doesn't even reach 10 MPH when it shift to 2nd, and I don't like the feeling of the engine trying to get up. Will do a transmission oil and filter change and in the future a trans kit, what do you guys recommmend for a kit? Ive seen some pretty good ones. I was thinking of rebuild with b&m kit(the complete kit that will make it similar to a b&m tranny). what other mods or adjustments will help?

Other than the previous problems, my car runs well. No other problems. When do you know that you need a new engine or rebuild? When it dies? or what are the symptoms before it happens? I know I will run this bird till it does pass out but until it does I want to enjoy the most of it.

Performance:
What do you guys recommend for better performance? I want to keep the stock engine and still run this mighty 2.8 until i get enough funds to upgrade.
pulleys?
new oil pump?
There isn't many perf upgrades, most won't keep it smog legal that I know of.


Thanks alot for your help in advance.

 

If you have some of that carb cleaner leftover, try cleaning the IAC. Idle RPM problems are frequently the result of dirty IAC pintles and air passages. You may have to remove and disassemble the IAC, clean, and lightly lubriucate it before assembly. You can SEARCH here for specific directions.

Of course you will need good plugs, wires, distributor cap and rotor. That's just part of a routine tune-up. Don't bother with anything but plain old copper-cored, single electrod spark plugs, and 8mm resistance wires. Get a decent distributor cap and rotor with brass terminals and GPR plastic material. Any number of parts manufactureres offer these, so it doesn't have to be a "designer" brand like Accel or MSD.

If the base ignition timing is set correctly, and the base timing doesn't wander noticably while you are setting it, disregard any timing chain problems. Even if the timing moves while setting the base timing, it may be a worn distributor instead of a timing chain.

Forget about the throttle response enhancers. You car worked just fine without it for the first 200K miles.

For decreasing fuel mileage, the oxygen sensor is always a suspect if it is more than 30,000 miles old, but in your case you need to repair the intake leak first. The O² cannot control the mixture if the mixture is being diluted by a vacuum leak.

A leaking intake will contribute to wandering, unstable idle, poor fuel economy, poor power production, and risks damage from running lean. Repairing that should be a priority.

Forget about a shift kit. Change the transmission oil and filter at specified intervals. Repairing your other problems may very well "solve" the shifting problems. Properly adjusting the TV cable can restore operation as well.

When your engine no longer produces adequate compression, burns more oil than gasoline, or suffers a catastrophic failure, you need to rebuild or replace it. Other than that, little else is insurmountable.

Most people looking for more power will look for more cubic inches. The 171 at peak performance might be good for 150-160HP without any kind of power adder. If that will be sufficient for you, just get it back in good running order. Personally, I'm not sold on underdrive sheaves for anything but the most "out there" applications, when an electric water pump should really be considered instead.

There is no reason to replace an oil pump unless you have definite lubrication problems. In that case, you'd likely be doing other things to the rotating assembly instead of just a pump.

 

I will search for instructions on cleaning up the IAC. I just want to make the car run as optimal as I can or at least as it used to. Your suggestions have proven helpful, as I think about it right now, the start of most of my problems was the leak on the manifold. And as you commented, it leads to variuos other problems. So this is my first priority. I will take care of that this weekend and take notice of any changes. This will probably fix most of my problems. I will also do the tune-up, any spark plug recommendations? I've been using AC Delco, will change the trans oil and filter, and adjust things as necessary. I will let you know how it went.
Thank you for all your help.