96 GT running rough....

[96redgt]

On my way to work this morning, after the car warmed up and I had driven a few miles, it started acting like it wasn't firing on all 8 cylinders. When coming from a stop at a stop light, or just after startup, it runs fine. After driving a few minutes (maybe a couple of miles), it starts acting up (shaking, "sputtering", slow acceleration, noticable exhaust noise). I glanced over the plug wires, but didnt see anything abnormal. I wont be able to look at it in detail until after work, but I was wondering if anyone had any ideas.

 

[white 98 gt]

when was the last time you did a tune up? maybe iac causing problems...

 

[Tbuck07]

Any codes being thrown?

 

[96redgt]

when was the last time you did a tune up? maybe iac causing problems...

I haven't done a tuneup since I got it in February. Its probably about time for one, though. What could be the issues with the IAC, and can it be easily remedied?

Any codes being thrown?

The Check Engine Light comes on and goes off, but has done that for a while. I will try to get the codes read tomorrow.

What is confuses me is that it doesn't do it while its sitting still, idling. It only does it after its been driving for a little while, and/or only after about 1/2 throttle. If I go light on the pedal, it doesn't do it. The moment I try to put the pedal down past 1/2 throttle, it starts.

 

[MustangChris]

when was the last time you did a tune up? maybe iac causing problems...

I haven't done a tuneup since I got it in February. Its probably about time for one, though. What could be the issues with the IAC, and can it be easily remedied?

Any codes being thrown?

The Check Engine Light comes on and goes off, but has done that for a while. I will try to get the codes read tomorrow.

What is confuses me is that it doesn't do it while its sitting still, idling. It only does it after its been driving for a little while, and/or only after about 1/2 throttle. If I go light on the pedal, it doesn't do it. The moment I try to put the pedal down past 1/2 throttle, it starts.

clean your mass air flow. its the metal cylinder on your intake pipe with the black box on top. Buy CNC mass air flow cleaner from Autozone ($4.99) and spray it sparingly on the two little wires in there. do not touch the wires.

use the same cleaner to clean your intake air temperature sensor. its the little electrical unit slightly higher up in the intake tube.

Then check your spark plugs, if one is broken or a wire is lose it could cause problems.

then your TPS (easy fix)

check your coil packs for cracks.

check your battery cables for corrosion and tears.

after that, it sounds to (me) like your iac is acting up (easy to fix)

check those things (along with your air filter) and let us know how it goes.

get those codes read.

 

[96redgt]

I'll run through that list tomorrow. Too late tonight to do it.

The first thing I thought was plugs/wires, because that's what it seemed like. What threw me off was the timing of when the problems occurred (driving instead of idling). I hadn't even thought of the MAF or the air temp sensor. Glad you pointed that out.

My negative cable on the battery had been corroded before, and I trimmed it back to clean copper then re-attached it. It cranks right up, so I don't think that's the problem (before when it was corroded, it acted like dead battery-no start). But then again, nothing is impossible.....

As far as the IAC goes, is there a way to repair/clean it, or is it just easier to replace it?

Thanks for the handy check list though!

 

[MustangChris]

iac is easy to clean.

the improper way of cleaning it (my way) is to take the vacuum line off the front of the throttle body, hold the hose with your thumb so it idles... and spray MAF cleaner into the throttle body port. lol. this is a very inefficient way of cleaning it, but its how i do it.

 

[96redgt]

Updaterove the stang to work this morning, babied it the whole way (under 2K Rpms/less than 1/2 throttle) and she didnt stutter at all. Going to pick up the maf cleaner @ lunch time. Hopefully it will be an easy fix.

 

[cobraclone]

i got the same problem. i cleaned all listed and checked plugs and wires / filters /air/fuel. last thing to go is the coils , so im thinking the prob lies there

 

[96redgt]

I just got back to work from autozone. I had two codes: misfire on cyl 3 and evap purge valve mechanical fault. i bought the maf cleaner and spark plugs.How do i check the evap purge problem?

 

[GDTrumbo]

The evap purge problem envolves a few items. An evap flow sensor and a evap flow solenoid. (both mounted on the firewall behind the cyl. head on pass. side). Might clean the connections but otherwise, both are un-servicable. Just replace. My '98 is showing this code on and off recently (#1443) About $75 for both at NAPA.

Then there is always the evap canister and another small item near the canister that I cannot remember the name of to save me. Both mounted in the RF fender. These items, thankfully, don't usually cause problems. These require fender or fender well removal to access. Replacement is the only fix here also.

Gotta love it......

GT

 

[96redgt]

Hmm.... I'll try cleaning the connections then. I don't have the money to replace that stuff @ the moment. Could the evap problems be related to my cylinder misfire in any way?

 

[GDTrumbo]

I don't think so. My CEL will come on somewhere over 30 mph or so and the ECM goes into "open" loop but never offers to miss. It just purges fuel fumes from the canister. Doesn't affect the ignition systems operation.

GT

 

[96redgt]

Eh, I need to go ahead and do a tune up anyways. Spark plugs this week, wires next week, etc... Having to do a tune up on a budget.

Anyways, @ home, relaxing for a few, then going to start screwing around w/ the stang. Will update as soon as I find a fix...........

Thanks for all the input so far guys!

 

[MustangChris]

here is where your purge tank valve is located

<img src="http://memimage.cardomain.com/ride_images/2/4359/1841/23395920052_large.jpg">

thats an orange handle screw-driver sitting ontop of it... its a small cylinder 9about the size of a roll of quarters)

remove the valve, spary it with MAF cleaner (inside and out) and reattach the valve. REMEBER WHICH WAY IT GOES ... obviously you dont want to put a vlave on backwards.

this is the only servicing you can do to the purge tank.

The carbon purge tank is located INSIDE the passenger side fender. It holds excess gas fumes and purges them when the car is at highway speeds and at normal operating temperatures. Chances are if you are getting the code, the valve isnt opening, or the canister (inside the fender) is broken. also, one of the lines could be kinked, bent, or broken.




"Could the evap problems be related to my cylinder misfire in any way?"
highly unlikely

 

[vermilion]

fords other ways to waste money on useless equipment.

 

[GDTrumbo]

No doubt!

GT

 

[96redgt]

Ok.... Removed the MAF, cleaned it. Removed the purge tank valve, cleaned it. Sprayed some MAF cleaner in the IAC. Sprayed some MAF cleaner on the air temp sensor. Checked the air filter, its good. Put it all back together, took it for a drive.... Seemed to run a good bit better, but then it started again. This time the CEL was flashing while it was acting up. When it stopped flashing, the car stopped acting up (once again it was when I started to keep it around 1/4 to 1/2 throttle).

Will probably do plugs tomorrow. I didn't see anything wrong w/ the #3cyl wire, but #6cyl wire does have a shallow cut in it. The coil packs seemed ok. The rest of the wires weren't close enough to affect each other. The fuel injectors were all plugged in nice and snug.

Any tips for doing the plugs on these motors? I can see I'm going to have to move a good bit out of the way.

 

[MustangChris]

sounds like plugs to me. when you do plugs, clean the boots on the wires, clean the outside of the wires (check for cracks,) clean the sockets on the coil packs (check for cracks,) replace the plugs, use die-electric gel (sparingly) on the boots on the wires. Also, use anti-sieze on the threads. Inspect the threads on each cylinder (you can use your pinky finger) to make sure all the threads are there.... (ford heads, particularly romeo if im not mistaken, shred their threads and push the plugs right out of the cyliner.) make sure the gap on the plugs are set properly. even if you get "pre-gapped" plugs...

i also suggest running a can of sea-foam through the gas tank (with shell premium gas)

if this doesnt work, my only other guess is to change o2 sensors... then i would break down and take it to a shop. :-(

(please note: you dont need to run premium every time. i just suggest it this one time for the "hot burn, cleaning" purposes...)

 

[96redgt]

If I can, I'm doing the plugs tomorrow. If not tomorrow, then the weekend. They look like they're going to be a PITA.

Sea Foam in the gas tank? Do I need to do anything special besides the premium?

I wont' be able to take it to a shop anytime soon.... No money to do that.... Hopefully plugs will fix the problem.

Will update as soon as possible.