Resolved Stuttering while driving, but accelerates good

[ohlegend]

I took my 98 Gst out for a drive today. The car will accelerate and boost perfectly, but when I let off the gas and try to keep a steady speed it will start stuttering and hesitating until I press on the gas. Under acceleration runs and sounds good. The car doesn't want to idle at stop signs (sometimes) or go slower than 40 mph. I am thinking that it is a throttle position issue. Maybe TPS is off or throttle cable isn't tight enough? Anyone else ever have this issue?

 

[highlandgst]

clean you throttle body either change or check the tps possibly even change your pcv valve on your valve cover those would be the easiest ones to deal with

 

[ohlegend]

Throttle is clean. I had a feeling that the tps might be off. You really think the pcv valve is shot?

 

[ohlegend]

I will try to get a log while driving to see where my throttle position is. It could be open to far or not open enough.

 

[ohlegend]

I might also add that when I'm coasting my vacuum is at 21hg and I boost up to 9-10psi

 

[ohlegend]

I just pulled my spark plugs. I had NGK BPR6EKN's in the car... So I swapped in my BR7ES'. I will take it for a drive later.

 

[ohlegend]

Still doing the stuttering. I noticed my TPS was loose. I am going to hook it up to my odbII reader and set it again.

 

[Talipse96]

I know that when the purge control valve is stuck open it tends to have the same issue that you're describing. When you open your gas cap is there pressure behind it?

 

[tylersevo]

Also check the ISC. You may have a bad coil.

 

[ohlegend]

Talipse, I will go out and check for pressure now.

 

[ohlegend]

There was no pressure when I opened the gas lid.

 

[ohlegend]

So what does no pressure when I open the gas lid mean? PCV is stuck open?

 

[ohlegend]

Not sure what the pressure in the gas tank means, but I have another pcv valve that I am going to try and swap out. Any other suggestions?

 

[ohlegend]

I did the blow through test on both of my PCVs, both passed. So I swapped them anyway. Just waiting for my tps to come in the mail.

 

[DSM Chase]

Highly likely its not the pcv valve at all... Sounds like a tune issue or bad maf, ensure there are zero boost leaks and or exhaust leaks. Fix that tps, Change the plugs, check wires and coils is also a good idea...

 

[Ludachris]

I had this exact problem with my mom's tt FD RX7. I went through the process of making sure the TPS was within the suggested voltage range and it fixed it. My 2g does this a little too and I think it's because I'm running a 1g N/T throttle body and the TPS and idle screw are slightly out of adjustment.

 

[ohlegend]

That is what I thought as well ludachris... (Plugs/Wires/Coils are new)
I bought a non-OEM tps and I think that is what is causing my issues.
What is the throttle position supposed to read at idle in neutral? Mine was at 0 with the SAS properly adjusted.
Now I have the sensor rotated all the way clockwise and I am at 9.8% at idle.

 

[Marc Pacheco]

I had this problem with my dsm a long time ago. Possibly something to do with the Maf mine had faulty wiring. Starts to spudder a little with no gas but was ok under full throttle. I would check your MAF and wiring to it. I had a bad wire.

 

[ohlegend]

Mine will coast fine, it is just when you feather the throttle to keep a steady speed.

 

[ohlegend]

I just got an OEM TPS, I set it where 3 and 4 loose continuity and 2 and 4 are between .4 and 1V (Mine was .73V) I'm going to give it a test drive tomorrow.

 

[ohlegend]

This fixed my problem. I swapped in a known working OEM TPS and properly set it.
It now drives smooth.