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Bogging down at high RPMS on my 3.8 2008 grand prix

C

Curt63084

New member
Ok guys so as of late Ive been having an issue with bogging down at very high, over 70 mph, speeds. But let me give a little back story. For about a year ive had a emission/vac code in my vehicle that never really had any issues, aside from it idling hard till the vehicle warms up, with the performance of my till the other night I was running hard on the free way. I was going 65 mph when I gunned it at as the TAC hit 5k rpms it started to bog bad and would not shift. Then a cylinder one misfire code came up. I did a turn up on this vehicle in the spring. I'm going to check the plug and wire going to cylinder one tomorrow but can anyone think of anything else?

Thanks
 


What is the other code, the vac code.

I wouldnt rule the other code out for a reason as to why this problem is going on now. A bad vacuum leak will be a heap of issues and because you said it already idles rough on start up, I'd really try to fix that issue aswell.
 
I check to make sure there wasnt a vac leak and I could not find one. The plugs were Delco Plats and they were delco wires as well. I just cleaned the MAF today. Interesting thing, I just had the code pulled today at Oriellys and they are only showing one code, P0300. So the code with the emission/vac/cat is gone.
 
^Bingo^

Oreilly's sells the AC Delco Iridiums- Part # : 41-101 $6.99ea. Stock replacements.

I have a set of these in my 95 Bonneville and 00 GT and they both run just fine. The wires break down long before the plugs do.
 


LOL, $7 a plug.

Just get copper cheapo Autolite 606's Gap them at .060". Move on with your car, $2 a plug. They last much longer than most people say they do. The motor will like them more as well compared to the other stuff. Been there, done this a million times. I'd put new wires on it too since you're in there. I'm sure it can't hurt anything.
 
You could run the coppers as blue pointed out. I did in my GT for a while. They did last longer than expected, but I drive a lot and didn't want to mess with them over and over, so I opted for the iridiums and new wires. Now it's just the wires that I replace when they start to break down. I average 30K mi/year on my car so I like to keep the maint. issues to a minimum.

Hopefully Curt doesn't mix up the wires when replacing them, lol.. Always fun times.
 
UPDATE:
plugs i have now are Plat plugs. New code came out, p0420. That is the code for the front side o2 sensor. Going to replace that tomorrow and see if that is the real reason all this **** is happening. If it doesnt solve the issue then ill buy the iridium plugs.thank you FFDP and Fordman for your help.
 
i'll put 10 bucks on the converter. and you should get rid of those platinum plugs regardless.
 


i wonder why the n/a cars seem to have clogged up cats more often then the supercharged engines? mine was original @ 232,000 and not clogged up.

seems rare on the sc cars really.
 
the other week i had a girl pull up on the other side of the gas pump. her car exhaust smelled like rotten eggs. i asked her if her cars been running bad and if it feels like it lost power. she said yes. i said do you have a check engine light on ? yes ... i said do you smell that rotten egg smell ? yes... i said you need a new catalytic converter ...she said what's that ? :th_laugh-lol2:
 
Pretty certain it isnt the cat. No smell, the cat is glowing red and I'm only getting these bogging issues when i stop on it at 65 mph or plus and the vehicle reaches over 5k RPMS.

SO the same code p0420 popped up again today. Any clues? Maybe the down stream is bad? AT THIS POINT there is NO OTHER CODE.
 
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