Hesitation/Stumbling

[soulnavigator]

I am having problems with my 3.0 FFV. Manual Transmission. It has 115k miles.

I have developed a hesitation or stumble as I accelerate. The problem does not occur when the engine is cold, but the more the engine warms, the more pronounced the stumble becomes. I have replaced an O2 sensor which was bad but not throwing a code, I have replaced all plugs, wires, and most recently the coil set. I also replaced the EGR sensor. I'm not sure where else to look.

Tonight for this first time in the entire process, the check engine light came on, which I will read the code tomorrow. I am just wondering what anyone else out there knows/thinks/etc. I have owned the truck for 3 years and aside from being underpowered, it has been great. But it's definitely not running correctly now.

I am out of money and would prefer to not have to replace any more parts which don't fix the problem.

HELP!!

Thanks!

Ryan.

 

[Viper Command]

you need to do a compression and leak down test.

I had seen with my own eyes ffv valves eat through exhaust valve seats, its not pretty

 

[soulnavigator]

you need to do a compression and leak down test.

I had seen with my own eyes ffv valves eat through exhaust valve seats, its not pretty

Wouldn't the problem be worse when it's cold and running rich if it were a compression/leak problem? I would think the engine warming up and parts expanding would cause the problem to lessen the hotter it gets...?

 

[Viper Command]

when its cold its in open loop, when it warms up its controlled by the computer.

 

[soulnavigator]

My brother had an older Ford and had the exact same symptoms with his...he ended up replacing the fuel pressure regulator. I know the 99 does not have this but has a fuel pressure damper. Do they serve the same function? Would this cause the problem I'm having?

I am now showing two codes: one is for the O2 sensor on the back of the catalytic converter and the other is a pending code relating to EGR valve -high voltage. Does either of these have anything to do with my stumbling symptom?

 

[Viper Command]

the egr can do that when it goes bad.