rough idle

[bigmerc281]

for a few days now i noticed on first start up after it drops to about 1k on the rpm its starts to shake lightly and the exhaust sound. sounds lopey.
anyone know how this can be fixed?

[Billy]

Sounds like it could be a little misfire.
It could be caused by a handful of things to be honest.
Do you remember the last time you replaced the plugs and/or coils? That's always the first thing I do whenever I'm having misfiring issues.

[bigmerc281]

Sounds like it could be a little misfire.
It could be caused by a handful of things to be honest.
Do you remember the last time you replaced the plugs and/or coils? That's always the first thing I do whenever I'm having misfiring issues.

Now that I think about its im a little over 1k due for a tune up thanks bud. Hopefully this fixes my dilema

[a_d_a_m]

My car has always had a rough idle. Even going back to the 1st owner, the OASIS shows problems with the idle.

Of course, now I'm overdue for plugs, a fuel filter, and probably a few other things...so it's REALLY rough. Ugh.

[justbob]

Mine has had a mild lopey cam sound ever since its first exhaust upgrade and most everything on mine IS new. Performance and fuel economy wise it is perfect so I have no problem with that.

Infact I am looking to get Comp's 106400 cams to make her even more aggressive sounding on the other short block, not to mention the power gains..

How's the car running besides the idle?

[Blackened300a]

I had idle issues due to my tune after installing the headers. After a cold start the engine would idle smooth, once it warmed up it idled rough and lopey. It was most noticeable when the winter gas was switched over. Recently I had a adjustment in my tune for more fuel off idle and part throttle and it smoothed out my idle completely.

[burt ragio]

Has a code resulted ?

[bigmerc281]

Has a code resulted ?
no not yet.

[bigmerc281]

Mine has had a mild lopey cam sound ever since its first exhaust upgrade and most everything on mine IS new. Performance and fuel economy wise it is perfect so I have no problem with that.

Infact I am looking to get Comp's 106400 cams to make her even more aggressive sounding on the other short block, not to mention the power gains..

How's the car running besides the idle?

It runs great. Its only on every other start up that I have this problem. If I clean the EGR do you think it will solve my issue?

[dohc324ci]

Mine has had a mild lopey cam sound ever since its first exhaust upgrade and most everything on mine IS new. Performance and fuel economy wise it is perfect so I have no problem with that.

Infact I am looking to get Comp's 106400 cams to make her even more aggressive sounding on the other short block, not to mention the power gains..

How's the car running besides the idle?

Nice 106400s are going to sound nasty on a 4.6! Bigmerc281 - how many miles do you have? Plugs/fuel filter are super easy to swap and cheap.

[bigmerc281]

Nice 106400s are going to sound nasty on a 4.6! Bigmerc281 - how many miles do you have? Plugs/fuel filter are super easy to swap and cheap.

I'm not sure when they were changed before I bought it at 64k it has 74k right now but might as well change them out

[justbob]

Cleaning the carbon out of the EGR is routine maintanence but I don't think you will see any change as its not scheduled to open untill you have reached highway speed. You can rule a vacuum leak out as these cars pop a MIL over the slightest leak usually plus it would be all the time. I would focus on the IAC not making a full travel (clean it really good) and replace the PCV valve as that could also cause a hit and miss choppy idle. Both of those are maintanence items anywho.

[justbob]

Nice 106400s are going to sound nasty on a 4.6! Bigmerc281 - how many miles do you have? Plugs/fuel filter are super easy to swap and cheap.

I sure hope so! The headaches I have been getting researching and learning heads.. They have never been my thing. Add the bee hive springs, seats, and head swap kit and the price makes the headaches worse!

[dohc324ci]

^^i wouldn't do just a cam swap by itself either. If doing as part of a build/refresh of heads then why not. 25-30rwhp on Mach Is I never did a before and after on GT40 to comps but on a big bore stroker those cams sound mild but they do lope and definatly rocks the car at idle.

[Vortech347]

Bump Old post but I'm having the same issue with mine. Only for the morning start it idles really rough when placed into reverse. Once I finish backing out of the driveway it's gone. The car will sound like it's missing or it's got huge cams. Everything else runs great. In fact it just averaged 21mpg last tank. Did you fix yours? I changed plugs with no difference, cleaned egr, iac, and MAF.

[Mebot]

Bump Old post but I'm having the same issue with mine. Only for the morning start it idles really rough when placed into reverse. Once I finish backing out of the driveway it's gone. The car will sound like it's missing or it's got huge cams. Everything else runs great. In fact it just averaged 21mpg last tank. Did you fix yours? I changed plugs with no difference, cleaned egr, iac, and MAF.


Quick bump here. Hi Vortech347 did you ever find a solution to your issue? My Marauder is doing the same exact thing: Rough idle upon start up. As soon as I go into reverse it idles rough, but once I finish backing up it's smooth.

Only thing I've done recently is recharge my CAI. Have not changed the COPS or plugs, but would that cause brief idling problems?

[rauder88]

Quick bump here. Hi Vortech347 did you ever find a solution to your issue? My Marauder is doing the same exact thing: Rough idle upon start up. As soon as I go into reverse it idles rough, but once I finish backing up it's smooth.

Only thing I've done recently is recharge my CAI. Have not changed the COPS or plugs, but would that cause brief idling problems?

I'd give the MAF a quick cleaning. May have gotten a little extra oil in the filter and coated the MAF. I've seen it happen.

[cheaneyt]

Try the iac valve .my ride did this for awhile then just wouldn't run unless I pushed gas pedal.

Sent while thinking of new mods for my 96 TC, using Tapatalk.

[Mebot]

Yeah, I'm going to be checking all the "usual suspects" (MAF, IAC, COPS etc..) I guess what I'm asking is what would cause the idle to be rough for 12-15 seconds then smooth out? If it's COPS wouldn't i continuously have misfire/rough idle?

[88LTDCV351]

My guess would be Idle Air Control Valve needs cleaned.

[Badass_forever]

on these cars, always start at the plugs, its very common for water to get down into the spark plug holes and swell the boots up. I would start there.

[BLACKMARAUDER04]

Check the hose that holds your PVC Valve. Mine collapsed and was
causing a rough idle

[CHSurvivor]

is there a link or video on cleaning the IAC here? If so please post :)
Thank you

[justbob]

Disconnect harness, remove two 8mm bolts, spray with MAF cleaner, air dry if it makes you feel all warm and fuzzy, reinstall not over tightening the bolts.


Builder Of Badassery

[JBeezy]

Disconnect harness, remove two 8mm bolts, spray with MAF cleaner, air dry if it makes you feel all warm and fuzzy, reinstall not over tightening the bolts.


Builder Of Badassery
If this doesn't solve it, remove IAC as stated above and clean it before you start throwing money at it. These possible fixes are cheap and easy.

[CHSurvivor]

There is no reset procedure?