Rough/Loping Idle, Hesitation, Sulfur Smell

[AquamanCHS]

A while back my car developed a small hesitation in the low-mid range cruising RPMs.. it would buck a little while cruising at 2000 and so I'd downshift and it was fine. Well, the problem seems to have developed further and now I have the following:

rough and lopey idle.. sounds and feels like I have a huge cam, definitely not VT stage 1; my exhaust note is also much more lopey throughout the entire range
stumbling on acceleration and i still have the hesitation at cruising
just recently I've started smelling a burning in my exhaust, smells kind of like the sulfur from fireworks
faint ticking/tapping in my exhaust note, as well.. though I can't hear this all the time

now, the idle is lopey/bad enough that to ease the car forward in first gear, i have to rev it up to about 2000 rpms to let the clutch out or else it'll jerk and buck out of control. if i try to launch relatively quickly, the RPMs will dip to around 1000 and the car will sputter and choke until i stab the throttle and the engine gets back up to speed. also, the lopiness is experienced at startup and can sometimes make it start up fairly rough.

what i'm considering so far is the EGR valve, something with the ignition or (hopefully not) something internal, maybe a piston, i dunno.

any help or suggestions would be greatly appreciated.

 

[slytherin]

How long have you had you catted X? Sulfur smell is usually indicative of a cat problem.

 

[AquamanCHS]

About seven or eight months, I got all the head/cam/exhaust work done around October last year. Could a failed EGR valve make the cats fail?

 

[AquamanCHS]

Bump.

I just went out and checked my spark plug boots and two of them (cylinders 5 and 7) had some soot/crap on the electric connection so I cleaned those off and used dielectric grease when I put them back on. It didn't change anything.

I might add the car never overheats.

 

[Mike97gt]

it's really hard too diag a problem like this without being there. but i would price out a set of motorcraft copper plugs and some wires.

ok just too help me try and rule out the plugs and wires. if you were at 2k rpms crusing and steped into the gas or went up a steep hill. does it buck?

the sulfer smell could be from excess feul in the exhaust.. it overwhelms the cats and causes this oder.

 

[AquamanCHS]

2k in which gear? in second or third it'll rev slower than normal, stumbling slightly... in 5th it'll just sit there and rev painfully slowly while making a kind of airy burbly hissing noise from the engine bay... neither times does it buck, i don't think.

also, excess gas in the exhaust? from perhaps.... a failed EGR valve?

thanks mike

 

[crazynorwegian]

mine did something similar to that, it ended up being a bad front o2 sensor

 

[AquamanCHS]

I changed my front O2 sensors less than a year ago. The car is also not throwing any codes.

 

[Mike97gt]

2k in which gear? in second or third it'll rev slower than normal, stumbling slightly... in 5th it'll just sit there and rev painfully slowly while making a kind of airy burbly hissing noise from the engine bay... neither times does it buck, i don't think.

also, excess gas in the exhaust? from perhaps.... a failed EGR valve?

thanks mike

no this is not related too a egr.. excessive fuel in the exhaust due too a misfire ( no spark. no fire = fuel leaving unburnt) this causes the sulfur smell. ( the reaction of the excess unburnt fuel causes this)

this will show up as a lean condition on that bank ( because the 02 sensor picks up only the excess unburnt oxegen, not the unburnt fuel) and this makes atleast one bank go rich making the problem worse.

well anyways. you probally just need a tune up. plugs and wires. don't get any fancy crap. just some copper motorcrafts.

BTW check your coils too. i can't help you any further than this without the car in front of me. . you need too pinpoint witch cylinder and what part is causing it. plug wire or coil.

 

[Mike97gt]

also, excess gas in the exhaust? from perhaps.... a failed EGR valve?

the only way the egr can pick up unburnt fuel is by pickign it up after a misfire. and it would have too be on the bank with the egr port on the manifold.

the egr is used too recirulate some exaust gasses back intot he intake charge.. since the exaust can not be burned a second time it takes up space in the combustion chamber as a non combustable gas. thus lowering the combustiuon chamber temprature.

this is done too lower NOX emmisions.

the only time a egr will cause a driveablility problem is if it was stuck partially open. and that should only affect idle. causing the car too stall. if it was open enough too effect part throttle operation then the car would have stalled at startup. becuase the egr would be open that same amount at idle and that would be too much. that amount of egr will stop combustion.

i still think this problem is igntion related

 

[Milenko]

I'm going to bump this, since I've been having the same problems.

Anyone find a fix?

 

[Red2000GT]

I had the exact problem and replacing one bad front o2 sensor fixed it,BUT you said its not throwing codes so i'd check for a vacuum leak. I played around with that a while back and could get my car to sound like it had a fat cam(which it didn't at the time).

 

[Milenko]

Just so everyone knows, I had ANOTHER bad front O2 sensor. It was showing 3 volts when it should show under 1. Replaced it, all is well.

 

[1fast03pony]

Just so everyone knows, I had ANOTHER bad front O2 sensor. It was showing 3 volts when it should show under 1. Replaced it, all is well.

was your car throwing codes? Im havin a similar (Barely noticable) hesitation with a slightly lopey idle and strong sulfur smell...

 

[sleepin89]

Ya know, its a damn shame we all have this problem, def bump me on this. I have a brand new motor and havent even been able to make it out of my driveway because of this problem, My car threw the P1158 code for the upstream 02 sensors being swapped, I changed em around and it cleared up alot to were I could actually drive the car but now I got a big time bucking and jerkin problem and its popping and all that other good stuff, Im outta options so if anyone knows a fix, please fill me in.

 

[01quickslvrstng]

Clean your MAF sensor and make sure it is clocked in the correct position. Also, you may have a failed catalytic convertor that is choking your exhaust and causing the overheating. Just some suggestions...

 

[Brute03]

i'm having the same problem too, i've already changes the plugs, fuel filter and cleaned the MAF but it still bucks and hesitates. the idle is fine but the car feels like a real turd

 

[GillsMotorworks]

Have same issue change the front 02s and egr and tps kept my iac valve new plugs and coils im lost here

 

[GillsMotorworks]

Its also not chipped and have a bbk in take it defi tley acts like it has a huge cam but idk just got the car and have that smell of running rich, then when i get on it sulfer smell

 

[RA200822]

My mustang is do the same lopey idle. But I just noticed it so it may just be the coil, will find out later today.
I am wondering if anyone on this topic who smelled the sulfur has actually checked their catalytic converters?
While driving my car I have never smelled it, however, there has been two or three different instances where I smelled that smell- but only while I was a passenger in my car, never while driving it. And the smell is not consistent.
Would a faulty 02 sensor cause the cat to fail?

(I am newISH to the whole mechanic thing, so forgive me if I sound like I don't know what I am talking about! Chances are if I am asking, its cause I don't. lol)