I'm hoping I can get some help here. Been trying for a few weeks now on other boards. My truck is a 98 f150 4.6l auto w/4x4. Still runs strong with 188k on the odometer. However, there are 2 things driving me insane.

1. The constant P0452 code. I am certain its the gas cap, but have not had time to pick up a new one. Its one of those caps that doesn't have threads, just twists slightly and thats it. No clicking to let you know it's locked.

2. The transmission or it feeling like the transmission pops out of gear when I hit a bump hard enough to jar the truck, even with new shocks.
When this happens, the truck feels like it comes out of gear, the rpms hover at whatever they were at, then drop to near stalling, then shot back up to the previous running rpms, then drop again before returning to the normal rpm the engine is actually at. Its at this point I can hit the gas and actually drive again. All this happens in a 5 second span.

My father-in-law thinks the above is related to the gas cap issue. I dont think so. Some have said it could be a sensor in the transmission, if so, which?

Or is it something else?

 

Do not waste money on a gas cap as it will NOT cause any of your reported conditions.

You might want to take the transmission issue to a qualified transmission shop for a proper diagnosis.

 

Why do the RPM's go all over the place like the engine wants to die and not just skyrocket while my foot is still on the gas? I mean when this problem happens, my foot is still on the gas till i realize the problem happened again, the rpms do not shoot to redline. But the engine is like bucking as if it's about to die.

 

Sounds like electrical issue to me. Cracked or corroded harness connections. You may not get a trouble code because it doesn't happen consistently. If it's actually something that simple, you may be able to warm up the truck, and carefully start wiggling fuel/ignition connections. Maybe you'll get lucky. ( Watch out for the fan) !!!!

Dave

 

ok im starting to think its just transmission related now. I should clarify that it only pops out or whatever it does once in a while when I hit a bump. NOT all the time. It did happen this morning when driving to work, hit a bump and it popped out while in overdrive.

Now what could cause this to happen?