So, I just bought a 2005 Monte Carlo LT (3.8 n/a) and when i go to about 4000rpm it's like i'm hitting the rev limiter. Car seems fine otherwise below 4000. Trans dosen't seems to be slipping from what I can tell, and shift fine if I keep it in the lower RPM.

It had 2 codes stored (P0350 and 1350). I cleared them, tried another known good ICM from my other car (L67). Codes have not come back but I'm still having the 4000 rpm issue.

It does it on acceleration or even on downshift. I tried every gear and it does it everytimes (well, i didn't tried 3rd and fourth up to 4000rpm, only on downshift because it would have been to fast on the road!).

I don't know if these codes are related to this issue or not, tomorrow I will try to swap just the 3 coil, but i don't think it will do anything because the car runs very well and got no misfire (I really think it is injector fuel shutoff)

I have DHP powertuner but it won't read the PCM. I can scan and clear DTC though.

So if anybody have any idea...

 

not exactly sure what your issue is, but...

- are you sure its the rev limiter? sounds more like a clogged cat...
- i had a similar issue once, but I am heavily modified and it turned out I was using wrong temp spark plugs.
- have you checked for vacuum leaks?
- bad spark plugs/wires will give you weird misfires that can feel like a rev limiter.
- go and double check your grounds. (ICM, block itself, fuse box)

after this I would consider finding someone with a scanner and logging whats happening when the issue comes up.

good luck.

 

BlackZ34:
Since you haven't yet filled out your profile, I don't know your name or where you hale from....

Welcome to the forum.
Theres plenty of people and info here forsure.... I'm sure someone will be able to help you resolve your problem.

Like mentioned before.... What maintenance has been done?
Tune-up, plugs wires,(what plugs are in it?) Filter oil change, Fuel filter, air filter, Maybe check the fuel pressure at the fuel rail...

Depending on where you live....There is a possibility someone from the forum in your area could scan the system properly to pin point why this issue is occurring!

Thanks for joining the MCF Family!
Feel free to join in on the conversation and stop in and say hi in the Daily Blog!

 

I might have found the problem.

Plugs looks new BUT they are Ac Delco # 41-993. From what I can tell these should be for a Monte Carlo 95-97 3.4 DOHC. The mechanic must have made an error when he put these on. I still have all (at least all the vendor wanted to give me!) the receipt from 2005 to date. He puts new spark plugs in september and they have approx 2000km.

So tomorrow I will get new spark plug Ac delco #41-101 like it should have. Or what do you think of the TR55 NGK ?

On the good side, these 41-993 will fit in my dads Chevy Express 4.3L so I wont trash them!

 

AC Delco! Always!

NGK

 

So I installed 6 new TR55 and went for a drive. As soon as I was on the road I floored it and it went well past 5000RPM. I tried to donwshift and everything was coorect. But after a couple of minutes (or when the car was up to temp...) it began to do the same thing.

It s**ks that I can't open the BIN with my DHP. I was checking some other BIN from others years and I think it may be the torque abuse mode or differantial abuse mode.

Tomorrow I will change the fuel filter anyway, and try to check if the cat is plugged by removing the front 02 sensor and drive without it so the back pressure have a place to escape if there is too much.

 

the plugs from a 95-97 DOHC are just one heat range colder then a stock plug for a 3800. that should not cause the issue. also a stock pcm will not cause a rev limiter at that rpm unless you are in park. I also would suggest that it could be a clogged cat. if the previous owner had been running a colder plug it is possible that the cat got clogged from a richer AF mix. even though the O2 should have corrected for most of it.

since you have a DHP, get a data log of it happening and post a screen shot of the data where it bogs down.

 

Code 350 is for coil, 1350 is for ignition coil module. Likely a bad icm. Possibly a bad or shorted park/neutral safety switch.

 

So I changed the fuel filter and it looks like I gained 1000 rpm. I checked the fuel pressure at idle and it is around 52psi. If I hold throttle around 3-4000rpm the pressure drops to 45psi within a seconds or 2. If i just rev it and let off immediatly it will go higher, like 55psi. I don't have a hose long enough on the gauge to go for a ride with it plugged in.

What are good numbers for fuel pressure?

The problem seems to occure mostly over 50% throttle.

BTW, car is stock and have 140 000km.

I did scanned it yesterday but saw nothing unusual. But for some reason I can't log 02sensor so I can't see what,s going on with this. Fuel trim looks right, I getting KR (sometimes over 6*) when WOT or near WOT. I think I may not have enough fuel at WOT.

 

OK, I did more testing this week-end. I checked fuel pressure while driving and got ~55psi at WOT so fuel pump is good. Then I removed the fuel rail and cleaned all injector with carb cleaner like I saw on some youtube video (like this except I used a 9v batt [link=]http://www.youtube.com/watch?v=7aT4S1lIBAY[/link]). Went for a drive and nothing changed.
Next I changed my 02 sensor, I had one laying around. Nothing changed.
Then I did a Case Learn, because the DHP is able to do this, nothing changed.
Then I removed the PCV valve and cleaned it with brake cleaner and compressed air, seems like it did the trick !