Thread: 2005 Grand Prix chugging

Fuel Filter clogged? Fuel injectors dirty? Just suggestions

Did you only clean the MAF? What about the throttle body itself? Is the air intake good and clear, filter? Even the type of filter can be more of a problem than a help. I tried a Purolator once that was so restrictive the car couldn't breathe very well.

Beyond that, whens the last time plugs, wires, PCV had any attention?

Have you had a scanner on it to see if it's throwing any codes that aren't triggering the MIL?

Just some thoughts..

Seems like the practical next step would be to check to see if the O2 sensors are working correctly and beyond that, the actual injectors. The thinking is the O2 sensors measurements are what tells the PCM to control fuel/air mixture and how much to feed the injectors. Fuel pressure could factor in but I dunno.

Another thought is something more simplistic is if any sort of injector cleaner has been run through the system or been running cheap fuel. Stuff like chevron's techron or shells v-power helps keep this in order but again, with the corn gas we've been getting stuck with isn't the best thing for injectors in the first place.

Again as I said before, you should run the gambit on sensors in the chain and make sure they are functioning within tolerances. Make sure stuff like PCV value is okay, throttle body is clean and clear. There are SO MANY things the computer makes adjustments on caused by sensor readings. If they're bogus, you'll have trouble.

I'm running a stock '05 computer and haven't had the problems you're describing.

ok guys, here it is. the cat. i have the same thing going on with my 97 and ive been discussing this with some guys. let me guess, when its cold and running high to warm up at a grand it doesnt do it, but after it warms up and goes into open loop it starts to "chug" but more like bogs right, but it doesnt do it all the time. its the cat, its backing up exhaust into the engine and cant reburn burnt fuel so it "chugs" or "bogs" down. believe me, it aint your injectors specially being newer cars. granted it wouldnt hurt to check your plugs and other routine maintenance. im getting ready to install headers and delete my cat.

damn Gorecki, just glancing over the thread again i noticed you're running tr55's. just curious as to why if you're not pushing alot of air through or fuel and you're stock? jw is all

Originally Posted by taman86

damn Gorecki, just glancing over the thread again i noticed you're running tr55's. just curious as to why if you're not pushing alot of air through or fuel and you're stock? jw is all

The TR55GP is a standard temperature platinum plug, essentially a stock alternative to delcos. I use NGK plugs and K&N Filters on all of my bikes so I simply went the same direction on my GP. Have to admit once I ditched the stocker stuff for what I have, I clearly have more power on demand and when I punch it over 3k on the tach and keep going I can tell it’s breathing much better and firing more smoothly. Really simple stuff made pretty noticeable differences.

Originally Posted by taman86

ok guys, here it is. the cat.

VERY good chance that could be a factor. But based on he pulled the MAF and it worked better on default tables means there could be something wicky about the MAP, PCV, and/or EGR?

right, if you unplug any air monitoring sensor (iat, maf, map, 02, etc.) forces the computer to go into closed loop mode which means it goes into speed density or relies on a preset fuel and spark tables without adjusting. with that, the preset fuel tables are rich to make sure the engine doesnt get damaged. more fuel being forced down a clogged cat means no chug, same as first start up while in warm up mode. but wierd though that if you turn the car off and turn it back on and the problem is gone, maybe a map or 02 sensor. try having the car scanned while its doing that. also, the computer wont throw a code unless there is a problem for an extended period of time

Originally Posted by Gorecki

The TR55GP is a standard temperature platinum plug, essentially a stock alternative to delcos. I use NGK plugs and K&N Filters on all of my bikes so I simply went the same direction on my GP. Have to admit once I ditched the stocker stuff for what I have, I clearly have more power on demand and when I punch it over 3k on the tach and keep going I can tell it’s breathing much better and firing more smoothly. Really simple stuff made pretty noticeable differences.

thats interesting but i guess the newer cars or maybe just being n/a is it. being s/c, the tr55's are two heat ranges colder and should be used when we force more air into the motor. on my t/a with a cam and intake i was running tr-6's, but i should've went to stock plugs or maybe even hotter when i went with larger injectors to make sure i was getting a good burn.