So ive got my 3.0 Ohv thats just being a pain. Its got 185k miles on it and ive changed out the fuel filter, tps, plugs and wires, and ive even had new cats put on. But shes still got a bit of rough idle. And she likes to take forever to build speed. So ill get to 40mph and itll take 3000rpm to do it. But if i try to go to 60mph i basically have to put my foot to the floor and hope. Now i do have a cracked valve cover and white smoke from the pipe when i try to make 60. But im just tryna make sense at this point. Ive run injection cleaners and everything through it. Its driving me nuts. Anyone got any ideas?

 

White smoke out the tail pipe is a blown head gasket, period

Cold engine
Rad cap off, top up radiator if its low, it should always be full to the very top all the time after engine cools down after driving, just FYI, its a self purging cooling system
Start engine and watch coolant at rad cap opening
Might get a initial "burp" of coolant at start up, but then it should just sit there
If level drops top it back up(you had air in the engine, not a good sign)
If it starts to overflow then for sure blown head gasket
Let it idle for 2 or 3 min. if its not overflowing
Then shut off engine, not a blown head gasket

Let us know about this test because there are other tests you can do if its NOT a blown head gasket

 

No overflow. Which is good because im broke lol

 

And the CEL(check engine light) is OFF when driving?
Computer will set Lean codes if fuel pressure is low enough to cause an issue

Air filter is clean?
And air passage from grill to air filter box is clean, no mouse house

Can you get your hands on a Vacuum gauge?
These are a cheap way to diagnose gasoline engine issues
18-21" of STEADY vacuum at idle is expected

Dollar Bill test at tail pipe can indicate Burnt exhaust valves
After engine is warmed up and idling use a dollar bill and hold it over the tail pipes exhaust flow
It should, of course, just push the dollar bill out away from tail pipe, if there is a rough idle, misfires, then the bill will drop a bit at each misfire, but SHOULD NOT be pulled back towards the tail pipe, i.e. sucked IN, this means a burnt exhaust valve

Try it on a friends car that has a smooth idle so you know what to look for


You have a 3.0l OHV Vulcan engine
Its makes best power/torque at 3,500-3,900RPMs, it was designed as a HIGH RPM engine
If you have a manual trans then do not shift until its over 3,500rpm
If Auto then shift it into 2 and don't shift into 3 or D until RPMs are higher, just to test if you are looking at normal low power below 3,000rpm

Most engines make best power/torque at 2,500-2,900rpm, so the 3.0l Vulcan can be confusing to drive, it was nick named 3.slow because of this design

 

Tail pipe is good. Gonna check with a gauge later today. And i tried what the other guy said again and this time it did overflow. And im getting a valve cover today so im hoping not having a big crack in it will help as well.