View Full Version : Spuddering problem when accelerating


Kyles03
04-15-2012, 09:28 PM
Hi all. I drove the car yesterday for the first time this year. Here's the problems that I noticed:

-It would be in high idle, like at 1100-1200 then settle down after about 5-10 seconds and then be normal. Could this be the throttle position sensor? I think thats what its called.

-First cruise yesterday it drove fine, accelerated fine through the gears, but everytime i would come to a stop in neutral it would do that high idle like said above.

-Second cruise something wasn't right. Going from 2nd to 3rd it would really spudder and seem to misfire (I think it misfired). I didn't notice if the check engine light came on at all, it wasn't on when I parked it.

Now I do have 3/4 tank of gas in it from last November when it went into storage, and i did not put fuel stabilizer in. I started it once a month over the winter. So could old gas be causing this? I plan to run the tank down to 1/4, fill it with new gas and change the fuel filter.

Thanks for helping a newb out!

TransamGCS
04-16-2012, 09:39 AM
things to look for would be a vacume leak, also check and clean the IAC, and check and clean the MAF with MAF cleaner

J-Bru-Ha Z-28
04-16-2012, 01:30 PM
Everything Transam said...it wouldn't hurt to drop a can of seafoam in the gas tank either.

Kyles03
04-16-2012, 02:48 PM
Thanks for the replies. Excuse me being a newb, but whats the IAC? And how do I check for a vaccum leak?

Also I had air intake system off for a short time over the winter, so maybe I accidently got the MAF dirty, so i'll clean that. I may drain the tank of gas, change the fuel filter and put in new gas and see what happens.

TransamGCS
04-16-2012, 07:23 PM
Thanks for the replies. Excuse me being a newb, but whats the IAC? And how do I check for a vaccum leak?

Also I had air intake system off for a short time over the winter, so maybe I accidently got the MAF dirty, so i'll clean that. I may drain the tank of gas, change the fuel filter and put in new gas and see what happens.

OP Nice ass Fire Hawk!! the IAC is the Ideal air control valve its on your throttle body just above the throttle position sensor, its a plunger that helps with ideal sometimes it gets sticky and dirty pull it from the throttle body and clean it with carb cleaner and check the o-ring, to try and find a vacuum leak somtimes you can spray carb cleaner and listen for a change in ideal, so you can spray around the intake manifold, vacuum line and any where else on the engine, one place to check is the hose where the pcv valve is somtime the boot around the pcv get dry rotted and cracks. when you clean the MAF make sure you use MAF cleaner and not carb cleaner or electrical contact cleaner these two items can leave a residue on your MAF. hope this helps and you find your problem

Kyles03
04-17-2012, 04:27 PM
Thanks for the help but I also don't know where the throttle position sensor is? I hope to work on it this weekend and see if I can fix it. I just don't know what I'm going to do with a half tank of gas lol.

TransamGCS
04-17-2012, 06:52 PM
Thanks for the help but I also don't know where the throttle position sensor is? I hope to work on it this weekend and see if I can fix it. I just don't know what I'm going to do with a half tank of gas lol.

on your throttle body you only have two sensors which will be on the driver side the top is the IAC the bottom is you TPS, i would try the sea foam in your gas i doubt its your gas it wasnt in storage that long if it was like a year or two old gas i would worry but not a few months

Kyles03
04-18-2012, 01:04 AM
on your throttle body you only have two sensors which will be on the driver side the top is the IAC the bottom is you TPS, i would try the sea foam in your gas i doubt its your gas it wasnt in storage that long if it was like a year or two old gas i would worry but not a few months

When I clean the IAC with carb cleaner, do I just spray it clean, and let air dry kinda like cleaning the MAF?

Instead of draining the tank then, I'll just put some seafoam in and fill it with new gas after cleaning the MAF and IAC. Hopefully that takes care of it. :confused:

TransamGCS
04-18-2012, 11:40 AM
When I clean the IAC with carb cleaner, do I just spray it clean, and let air dry kinda like cleaning the MAF?

Instead of draining the tank then, I'll just put some seafoam in and fill it with new gas after cleaning the MAF and IAC. Hopefully that takes care of it. :confused:

you can spray the plunger and wipe it with a rag and spray a little on a rag and wipe the inside of throttle body and let air dry

Kyles03
04-18-2012, 11:53 AM
you can spray the plunger and wipe it with a rag and spray a little on a rag and wipe the inside of throttle body and let air dry

Thanks again man! :)

wicked383lt1
04-18-2012, 12:04 PM
I had a similar problem and changed IAC my car runs great.

Kyles03
04-18-2012, 04:41 PM
I had a similar problem and changed IAC my car runs great.

Buying a new one at a parts store or what?


And what problems were you having exactly, the higher idle or spuddering and running like shit while accelerating?

bad_408_vert
04-18-2012, 05:48 PM
you can siphon the gas into a gas container.

All 8 gallons...idk where you could discard it.

Kyles03
04-22-2012, 07:24 PM
Aright guys I cleaned the MAF and IAC, took the car for a drive and the check engine light came on and it threw a PO300 code random misfire.


After searching on the site, people have said to replace plugs, wires, fuel filter and some other things.

I also noticed this PCV valve hose was cracked and aged:

http://i269.photobucket.com/albums/jj62/KaPolarisman/279f87cf.jpg


I am replacing the PCV valve and that hose. I also added seafoam to the existing gas, but I don't think the gas is the issue anymore. I still plan on putting a new fuel filter in. What else should I do since it threw that code?

DisasterFormula
04-22-2012, 09:36 PM
A bad pcv valve can do a lot of bad juju to a car. My friend's 99 Ford Escort had a vacuum hose w/ a hole about the size of a quarter in it. It idled high and liked to die when she came to a stop.

Also, I think your missfire is gonna be from the bad gas, too. Probably got varnish in your fuel lines and filter.

_JB_
04-23-2012, 01:23 AM
The gas is fine unless you got water in it.

J-Bru-Ha Z-28
04-23-2012, 01:28 PM
Replace the PCV hose and see what happens...I had my PCV hose fall apart on me once too, never got the code but the thing would surge and die at a light sometimes. Didn't take long to find that vacuum leak though since it was the short piece of hose between the PCV valve and the TB.

Kyles03
05-28-2012, 07:08 PM
Just an update but the problem got worse. I brought it into a local mechanic and the whole drivers side of the motor was not firing. The plugs were shot along with the o2 sensor. He also did a compression and fuel pressure test, he said they were both good. What would cause all the carbon build up? My driving style may be the cause of that, short trips, not running the car hard, and starting it up once a month over the winter and not driving it.

Could the combination of the big cam and my driving style have been the leading cause to this? I'm now considering a mild-er cam with less lift.

DisasterFormula
05-29-2012, 09:56 AM
The big question: Did you get a tune after the cam?

Kyles03
05-29-2012, 08:23 PM
The big question: Did you get a tune after the cam?

It was dyno tuned by a performance shop over 5 years ago when the cam swap was done.