Need some ideas on engine behavior

[George Blake]

During cold weather, the engine has to crank and crank to start.
Shakes like a mother.
During warm weather. One thunk and it fires right up and runs a LOT smoother than in cold weather. I did the EGR delete but haven't done the prom change to disable it. No codes. It's got new plugs. Old wires and cap. Could that take care of it? I also deleted the cruise control and the vac ball. I used the chart on the fan shroud so as not to miss anything and replaced all the vac lines.

 

[turbodig]

Re: Need some ideas on engine behavior

During cold weather, the engine has to crank and crank to start.
Shakes like a mother.
During warm weather. One thunk and it fires right up and runs a LOT smoother than in cold weather. I did the EGR delete but haven't done the prom change to disable it. No codes. It's got new plugs. Old wires and cap. Could that take care of it? I also deleted the cruise control and the vac ball. I used the chart on the fan shroud so as not to miss anything and replaced all the vac lines.

Stock chip?

Fuel pressure is ?

Big vacuum leak would be my first instinct... engine heats up, parts expand, seal the leak.
Maybe the intake gasket?

 

[George Blake]

Re: Need some ideas on engine behavior

Stock chip?

Fuel pressure is ?

Big vacuum leak would be my first instinct... engine heats up, parts expand, seal the leak.
Maybe the intake gasket?

I've gotta go through the whole thing to get current but AFPR is 45 PSI. Stock chip.
I know my alternator is bad. I'm gonna swap it out to the new unit and then do cap and wires. I bet I've got a vac leak. Upper intake and lower intake have never been off.

 

[WyoSyclone]

Re: Need some ideas on engine behavior

I've gotta go through the whole thing to get current but AFPR is 45 PSI. Stock chip.
I know my alternator is bad. I'm gonna swap it out to the new unit and then do cap and wires. I bet I've got a vac leak. Upper intake and lower intake have never been off.

...wonder if the IAC valve is operating like it should. Does it idle fast during a cold start? If the IAC is stuck, or not moving enough to raise rpm's during a cold start maybe it's running way rich at startup??

 

[Syclone #1721]

Re: Need some ideas on engine behavior

I vote for the vac leak on the lower intake. Mine ran very much like you are describing before I changed it out.

 

[Syclone#892]

Re: Need some ideas on engine behavior

Bad coolant temp sensor? Sensor could be showing wrong temp and causing a problem, i've seen it on plenty other vehicles so I wouldn't doubt on a 16 yr old vehicle that it could be bad. Plus they are cheap enough to replace just because of its age. Good luck on what you find.