Originally Posted by regis101
Why do you think that?
Another thing to check is the throttle body is opening all the way if you suspect power levels are low
A while ago I had a coolant leak in the intake manifold getting into the spark plugs causing cylinder 7-8 to misfire, as I was remote I had to drive the van up some sketchy terrain, a bad smell was coming out of the escape after a long slow climb...
I went to the dealership which replaced the intake manifold and many other parts (sparks, coils, gasket ....) after $2k the van was running normal, no misfire.
When they delivered it to me, they told me it feels like it doesn't have power and they suspected that the cat was clogged out of all the driving I did and the symptoms.
Since they wanted to charge me a lot more money just to get it back pressure tested, I researched a little bit and realized it wasn't rocket science if you have the right tool, so I decided to get away from that money hole and DIY.
So I've been driving it all of these days, after around 10k miles I can tell that even though the van has good low-speed power, when going on the highway @65 and hitting a climb it starts losing momentum, downshifting and trying to get to higher RPMs, this did not happen before the misfire. I'm not towing either have a heavy rig. I'm currently running 245 tires which is the max you can put in a stock.
I want to start with the low hanging fruit first, then go and check other parts since my mechanical knowledge is limited. Hopefully, I'll hit the jackpot.