Loss of Power

[roenick778]

I have had my P5 now for going on 3 years, I realized it was under powered from the get go. Lately it seems that it has lost more of its get up and go. It could be its so hot in Phoenix, and that i run the a/c all the time this time of year. I took it to the dealer about 4 months ago , just for an oil change, i normaly do these myslef , but every once in a while i like to take the car in to the dealer because they usualy give me a luandry list of things they think it needs done. I was told it needed new spark plugs, which i put in, it needed the rubber boot ( cant think of the technical term of that part now) replaced, as these tend to crack with age. i have yet to replace it, it does look like it is cracking , but doesnt look like it has completely failed at this point. its a $60 part and i plan to replace it soon. The air filter is pretty good on it, so i dont think that is the issue. Some stats about the car, its a 2002 , has about 95 k on it now and i have yet to replace the timing belt ( 105 k recomened) could it be the timing belt is strecthed or the tensioner is failing causeing the loss of power? The car is a manual transmission and REALLY isnt working for me now, i picked up a part time job here i am doing a TON of driving , lots of stop and go and backing and turning and stuff which i realize is hard on the car in general. My plans are to try and sell it and buy something with an auto transmission. I also know it needs at least 2 motor mounts, ( not sure which 2 off the top of my head) in teh condition its in i dont think it would be easy to sell, and i dont want to have to put alot of money into it just to sell it. I guess my question is what could be causeing the loss of power and suggested cheap fixes. I also noticed that even after chaging the spark plugs it seems to stumble throught the accelaertion band. I askked if it needed new plug wires when the dealer gave me the list of things they recomened fixed and they said they usualy dont replace them . I'm racking up 100's of extra miles a week with this part time job and want to get this thing working better cause its annoying to drive at this point plus i doubt anyone would be too serios about buying it as it just seems "off" to me at this point. (pissed),(shrug)

 

[hotcracker69]

injector cleaner?

 

[conewagon]

did you gap the spark plugs? .44 for our cars I believe.

 

[Tzar177]

Replace coils and wires? Cleaned EGR valve? Maybe clogged cat converter? Exhaust leak?

 

[RABID_MP5]

one theory is if the A/C is low on refrigerant the compressor will be running all the time. This would definitely take a chunk out of performance.

 

[roenick778]

Plugs were gapped. The a/c compressor DOESN"T run all the time? Didn't know that, assumed it did run all the time the a/c was "on" . Havent done anything with EGR at this point nor the injectors. Looks like i have more to do on this car. Thanks for the replys!!

 

[wcprotege]

The air intake hose can be replaced for a lot less than $60. I bought a new one off of Amazon for around $28.00 plus shipping. Do a search for Dorman air intake hose and you find it. I was a little worried the quality wouldn't be all that good when I bought it, but it's fine and certainly works better than the hose that was on my car that was nearly broken in half.

As for an EGR valve, the one I've seen recommended here can be purchased at Rock Auto and is the Canadian version. Part #EGV1124. Look under year 2000. It won't show up under the 3rd Gen cars.

 

[hotcracker69]

Plugs were gapped. The a/c compressor DOESN"T run all the time? Didn't know that, assumed it did run all the time the a/c was "on" . Havent done anything with EGR at this point nor the injectors. Looks like i have more to do on this car. Thanks for the replys!!

at least these are all things that you can do for under 50 bucks.

 

[P-Funk!]

one theory is if the A/C is low on refrigerant the compressor will be running all the time. This would definitely take a chunk out of performance.

No, when low on refridgerant (sp?) - the low charge switch is made and the compresoor will NOT engage (to protect it).

 

[P-Funk!]

I would run injector cleaner through it, seafoam the engine, and check for a clogged cat first... (unbolt it and see if it dramatically improves performance).

 

[slavrenz]

I would run injector cleaner through it, seafoam the engine, and check for a clogged cat first... (unbolt it and see if it dramatically improves performance).

He could also check for clogged exhaust with a vacuum gauge - much easier IMHO.

 

[StevieB32]

First off, no CEL? I'd confirm the CEL bulb is ok, just to be sure.
I agree with the fuel injector cleaner suggestion-I use the stuff on a regular basis. My 02 was gutless(160k kms-100K miles), then started spitting out random misfire and warmup cat CEL codes. Changing the coils(Autozone Duratec-$28 ea-budget friendly) eliminated the misfire CEL, and the power and smoothness of the engine increased very noticeably, as did the gas mileage. Replacing the warmup cat with a header has had little added impact on power, so it seems the cat was not blocked in my case. Good luck!
P.S.-I tested the old coils before replacement, and they were within spec.

 

[P-Funk!]

Make me smarter - how do you diagnose clogged exhaust path with a vacuum gauge?

Low vacuum at idle? How do you know what is correct vacuum and what is 'low'?

 

[slavrenz]

Make me smarter - how do you diagnose clogged exhaust path with a vacuum gauge?

Low vacuum at idle? How do you know what is correct vacuum and what is 'low'?

Normal vacuum at idle for most cars is about 17-22 inHg. Muscle cars with high valve lift or long duration will see a vacuum reading a little lower (around 15 inHg) due to valve overlap.

To diagnose a clogged exhaust, you have to know what normally happens with your vacuum gauge. When you accelerate, the gauge will momentarily drop near zero (throttle plate opened, engine exposed to atmospheric pressure), and then will go back up to your normal reading. If you have a clogged exhaust, the needle will not return to normal, due to excessive backpressure in the exhaust.

In fact, if you let the engine idle for a while with a clogged exhaust the needle will normally creep lower on its own, due to that same backpressure.