Loss of Power When Warm

[vintageagain]

Ok so my car was having some serious power issues and thew some codes. they were cyl 1 and 4 were misfiring. I was due for a spark plug change so i changed them and replaced the 1&4 coil. Went out for a test ride and while the car was cold everything was fine. Once it warmed up and my RPMs were greater than 2k the car made a drone and seemed to loose power. Any ideas? I replaced the wires 15k miles ago along with the fuel filter.

[deftons56]

Re: Loss of Power When Warm

replace the spark plug wires?

[Turbo V6 Camaro]

Re: Loss of Power When Warm

could be the CAT

any other codes?

check those plug wires for burns

[vintageagain]

Re: Loss of Power When Warm

I bought the blue taylor wires - at the coil there are some browning marks right before the boot. tomorrow i'm going to try and read the resistance of the wires to see if there is consitancy or not.

There were no other codes, other than the two cyl misfiring.

[Turbo V6 Camaro]

Re: Loss of Power When Warm

brown ones mean they are arching

[vintageagain]

Re: Loss of Power When Warm

So far:

My car has 115k on the clock.

1. I replaced the plugs: I was able to run the car up to 40mph then it would get warm and bog down.

2. I had 2 new coils so i replaced 3&6's stock coil: no change so i put the old one back on.

3. I replaced the ICM: no change so i put the old one back in.

4. I replaced the wires and tubed them: I now can get beyoned 40mph with no problem but acceleration is terrible.

Alright so i changed the wires and now i have a decent top end. I can get to 70 mph now without the engine telling me no at 50. But i still can't accelerate like i use to. At high RPMs ( about 4-5k in 2nd around 50 mph) the car starts to make some weird noises - such as a whine or deep whistle. My first thought was vaccum leak. So i took off the sensor on the pass side near one of the vaccum tubes. I ran the car and there was no change - not even a code which i was hoping for. I replaced the sensor and crawled under the car and had my brother rev the engine. On the pass side i could hear some rattling of metal/ect coming from my Cat when reved.

Also, while the vehicle was runing i had an OBDII connected. I noticed that the Fuel Sys 1 and 2 were opeining and closing. Should it stay open?

So now i'm looking for a Cat. I'm not into performance with this car (at the moment) so any suggestions on a decent OEM replacement? Or is there any benefit for a high flow cat without the rest of the exhaust being done?

[Firebirdkid96]

Re: Loss of Power When Warm

Could be the cat,

magnaflow makes a decent aftermarket cat, it's about $100, but it's OBDII approved, and yes, it's a high flow cat, but it's not going to give you amazing horsepower gains...even with the stock exhaust, it should still free up a little bit of exhaust restriction.

[vintageagain]

Re: Loss of Power When Warm

Ok so i decided to go with a stock cat since some of my research points me to minimal gain (even with headers and new tail pipes/muffler and i need to maintain emissions.

Alright i crawled under the car to get a look at the cat and....the damn cat is welded to the Y pipe. So for people who have changed their cat, did you just cut it off, use a reducer-flange-ubolts, and put it back together?

[jutt26]

Re: Loss of Power When Warm

Possibly the coolant sensor starting to go so the computer doesnt adjust the fuel mixture correctly? Although once up to temp I would thing your idle and acceration throughout the band would be acting weird too if that was the case.

Just a random thought.

[vintageagain]

Re: Loss of Power When Warm

Update for Records:

Had the cat replaced for $214. $100 for the cat, and pipe coming out of the rear of the cat with the hole for the O2 sensor. $100 for labor and 14 for a 2 yr warrenty.

Car runs great!