Stuck in 2nd gear??

[DenaliHD66]

So, in an attempted to correct my misfire problem, I've been running seafoam through the intake/vacuum line to try to clean out the valves. So I warm the truck up and drive it around, then I pour the seafoam in. I let it sit, then I fire it up, takes a couple cranks to get it going, then I rev it in park. Then, after a nice long burn, I shift into the "hidden gear" [aka unlimited rev mode] and revved it up even higher. Then I went for a drive--not having turned it off in between-- and i jump on the road and notice it starts in 2nd gear and doesn't up or down shift at all. So i drive to the gas station to fill it up, and upon startup again, it ran perfectly fine. Did the "secret gear" effect this or something? It was almost like it was under reduced engine power, but no lights ever came on. All i know is that it was in 2nd gear the whole trip to the gas station and didn't shift at all. Reverse/neutral/park still worked fine though. Any thoughts?

 

[BoldAdventure]

Usually when the car stays in 2nd or 3rd gear only, it's a sign that the ECM has gone into limp home mode.

 

[Pittdawg]

Usually when the car stays in 2nd or 3rd gear only, it's a sign that the ECM has gone into limp home mode.

Or that you have been listening to the "Friends" theme song too much

 

[DenaliHD66]

Or that you have been listening to the "Friends" theme song too much

LOL that popped into my head too

Usually when the car stays in 2nd or 3rd gear only, it's a sign that the ECM has gone into limp home mode.

That's what I kinda figured.

 

[CaptainXL]

What codes do you have?

 

[DenaliHD66]

No idea didn't scan it.

 

[mrphoenix80]

A code check could tell you but if it was normal after the key cycle I would have to say that you caused the PCM to freak out and it went into limp mode.

Or that you have been listening to the "Friends" theme song too much

When I read the title I got the old song "Beep Beep" going in my head. "HEY Buddy. How do I get this thing out of second gear!"

 

[CaptainXL]

No idea didn't scan it.

Well scan it. First step in diagnosing computer controlled vehicles my friend. Make it a habit. Everyone on this forum that fixes their own vehicle should have a scan tool of some kind in the top shelf of their toolbox.

 

[DenaliHD66]

Think it was just in 'limp' mode as everyone else indicated. It runs perfectly fine now. Also, if you are one of the people who cut off your exhaust resonator, and you seafoam your truck, expect the interior to smell badly of carbon. My tailpipe fell off a few months ago at the rear hanger, so it exits 2 feet under the truck instead of out the back. Low priority list for right now.

 

[CaptainXL]

I've read so many articles on different forums from senior members that say Seafoam is a bunch of crap. Its just kerosene and isopropyl alcohol. That in itself is enough for me to stay away. What you really need is GM Top Engine Cleaner through the fuel rail. Dont put it in the tank. Also use GM fuel injector cleaner or Chevron Techron Concentrate Plus . They are the same thing and contain PEA.

 

[DenaliHD66]

What is PEA?

 

[CaptainXL]

What is PEA?

What % pea? - Bob Is The Oil Guy