Every once in a while, after I start the car, I watch the rpms rev up slightly and then down. Almost to the point of stalling. It never stalls while it is doing this, unless I put it in gear. It doesn't happen all the time, but it happens often enough to wonder what is causing this erractic behavior. Any ideas where to start?

Oh yeah, I've replaced EGR, plugs, wires, and module not too long ago. The car also has an open element with the IAT sensor located in the underside of the filter housing. I have installed a FP gauge, just gotta wait for it to happen again to see if it is a fuel pressure problem.

 

I'm having the same problem. I am going to change the fuel filter and see if the problem goes away. I would also recommend checking for any stored codes.
Does it do this when the outside temp is very cold, or does it matter?


...Firechicken.....

BTW, I see you have done some tune up items, have you also replaced the cap, rotor and coil too?

 

have you guys checked your coil?i had a major idling problem when i found that the tabs for the connector were broken and made it wiggle when the engine was running.if it`s loose that could be your problem check it out

 

robertfrank, hey thanks for the tip. i have yet to replace any of my ignition components. i was looking at a set from Summit that is made by Hypertech. Anyone have any opinions on this company/products? They seem to be selling a cap, rotor, and coil kit for around 72 bux IIRC.

 

I have an update to my stumbling problem that might help you out. I finally was able to get to check the FP when the car was doing it's stumble-dance. I watched as my FP was bouncing between 8-9 Psi. I also looked at the back of the car to see some pretty heavy grey smoke, that did not smell like gas, so I imagine that it was very lean(?)
The car has also stalled out on me twice. Each time, after I had to apply the brakes in a hurry. I would guess that the fuel pump is not able to feed enough pressure, with the sudden loss of momentum.
Either way, it is starting to point to the signs of a dying pump, so I have a new HP TBI pump on the way.
I also went out and spent some money on a few other items that I will be replacing:

IAC valve, O2 sensor, PCV valve, cap, and rotor.
(BTW, is there any special procedure that I need to do to install the new IAC? I thought there was some kind of measurement that the cone was not supposed to exceed?)

I am also getting ready to order a new coil from Summit. Which one do you guys think I should get? The Summit brand, the MSD, or the Crane?

BTW, why does this thread have a black dot over the the icon?

 

also you might want to check to see if you have a leaky injector.take off your air cleaner lid while the engine does this and watch how they fire.i recently discovered this after ALL of thie thinhs i`ve been throwing at my car.one of my injectors seem like it`s just dripping feul and the other doesn`t spray mucj at all or very little,but the weird thing is if i let the car sit and warm up it doesn`t do it quite as bad.jsut take a look to see if that could be your probalem as well.on a final note about what coil to choose i say go with msd,i`ve got one and it seems to work fairly well.

 

sorry about the spelling i just woke up

 

Yep, already checked to see if I had an injector leaking, but everything there looked okay. I pressurized the system and pinched off the fuel lines, and the pressure held. Well, until I let go of the return line, then it dropped to 0. So I am to the point of replacing the pump, just to be on the safe side.
The pump showed up at my door step this morning so it looks like I will have a weekend project going on...
Got called-in early to work, so O2, new pads, and PCV will have to wait again until this morning.
I did order the MSD, and that should be here in a few days. At which time, I plan to do the cap, rotor, and coil all together.
I'll keep everybody posted on the progress.

 

Well...you've never answered about your progress. Did you get the pump installed, or any of the other parts you have?
I am still trying to figure out what is causing this stumbling.

 

Sorry about that. I honestly forgot about this thread until it popped up today. I did replace the cap, coil, rotor, factory module, wires, plugs, O2, and IAC. And it still runs the same exact way.
I am getting ready to do a bunch more things in the near future, including a higher pressure fuel pump, that i hope will solve some of these seemingly fuel related problems.

 

damn, i think we have the same car....lol

but yours has had more work done to it