dillon410021

My car has been acting up again. On start up, it will start okay but will miss or not run correctly. It usually goes away once you drive it for a couple miles and the idle will even out . Lately, It will Idle very low right after start then rev itself to about 1,500 rpm then start to idle. When at the low idle, it is not very loud and seems like its running on 1-2 cylinders. During the first mile of driving, it will stumble and not accelerate fast at all. Its like it has 100 hp. It also has good days and bad days. The weather doesn't matter but on some days the boost will roll on sluggishly and not correctly and it feels slow, but on some days, it will throw you back in your seat. It start up fast on hot start ups but I did once rev itself to 2,000 and hold it there until I let the clutch out in gear. The spring on the throttle is good. Would any of these point to the reference sensors which I am not sure have been replaced. Another thing id the 02 sensor. Could it be the 02 sensor? The TPS is new and working. The car has autothority stage II chips and MAF. Could it be the chips? I have searched but haven't found what I need. All comment will be appreciated. Thanks in advance.

Jeff N.

Here's a couple ideas:

- clean your MAF wire with MAF cleaner. I've had some strange issues due a dirty MAF. Simple to do.

- any chance you have moisture in the cap or plug wires? Sounds a bit like the ignition is shorting. Sometimes you can see cold run problems until the car heats up enough for the moisture to dry out. Try pulling the cap when it's cold and likely to do the problem and see if you have strange stuff in there.

- have you checked for vacuum or pressure track leaks? So many problems on these cars seem to come back to this.

dillon410021

I will check the first two. The vacuum lines are all new (L.R. silicon)

ehall

Yes, if you don't know when'if the speed and ref sensor wires have been changed, do that, but first find out if they are bad. Wiggle them and feel for breaks and splits in the heat shielding.
Change the plugs.
Have you ever replaced the fuel filter?
Those two, either alone or together can do that.
Start simple.

dillon410021

The reference sensors were screwed with by the PO. He took the plug connector off the sensor side on both sensors and plugged it into the engine harness,then covered it with silicon. How about the 02 sensor?

xsboost90

sounds like when my vac. hose came off the fuel pressure regulator. Car would run super rich and flood out, hardly run until it blew itself out after driving. Eventually it just wouldnt start. Found the hose off and zip tied the hose - all of them!

dillon410021

I just installed a 3 bar FPR but the problem occurred way before I installed this.

sebastian944

might be the chips, i have the same type. I have this problem, it's just inconstant .. and dependent on weather. Buy the Vitesse setup for less issues. Just my opinion..

sebastian944

I have the same issues. It corrects itself if i drive the car more often though. I should change the ignition setup though, I have no idea how old it is.

dillon410021

I wonder if it is the chips. I still want to know I can run Max chips with the autothority MAF

ehall

Why are you jumping to the O2 sensor?

I'm not sure what the PO did, but I think you should go back to the suggestions of Jeff and myself, before you go grasping at straws.
Keep It Simple Stupid.
Eliminate the obvious FIRST!
Go from there.

ehall

Oh and the sensor wires connect to two wires that go to the DME, etc. They can be bad on that side, rather than the sensor side.

dillon410021

How can I test the harness going to the dme?

Bill

If the cold start idle is low and then the idle problem goes away after the engine warms up, I would first check the coolant temp sensor, then check the auxiliary air regulator.

Jeff N.

Don't make this hard yet. There's lots of opportunity for that later. Ehall's right. If your description is accurate, you have a cold run problem. Sounds like it runs fine when warm - does it?

Cold run problems tend to be sensor (wrong reading), spark (poor spark) or fuel (too much, not enough) related. I doubt you have a harness issue unless you are having moisture issues that are causing a spark or a sensor problem.

O2 sensors typically doesn't come into play until the car's warm. Mixture's too rich during cold run and the sensor is ignored until up to temp. O2 sensors problems will tend to be either warm idle or warm mid throttle problems when the car is running closed loop.