My problem is a idle miss and hesitation/sluggish performance while driving. The idle miss becomes bad when I take the RPM's up to around 1000 and when driving at take off and afterwards I get sputering no performance and sometimes i hear what sounds like a intake backfire (Only when I push hard on the pedal). I have replaced or checked the following parts.

92 RS 3.1L 5 Spd Man
Distriubutor (Persision Tune Recommended) here after known as (PT)
Alternator (PS) Said bad diode
Cap/ Rotor
O2 sensor
MAP checked
Fuel Filter
Added B12 Injector cleaner
Gas line dryer
IAS
TPS
Bosch wires (5 months old) no crack detected
AC RapidFires (5 months old)

Have reset and rechecked timing and firing order

Any Ideas?

 

It may be your EGR valve acting up

 

Forgot to post that, the EGR was the first thing I checked. I have digital EGR and I disconnected it car ran worse. I was thinking maybe the Water Temp sensor?

 

I'd venture to guess it's the timing... if you hear an intake backfire it's either running lean or it's too far retarded... With my car timed 2* advanced from stock setting it still ran like complete ***... I advanced it a good deal more and I'm finally happy... no more intake backfire... in your case... run a few tanks of 87 octane... advance, run a hard trip uphill (checking for knock counts would be the better idea, but listening for audible knock works) and advance till you heard audible knock, back off a bit by bit till no hint of audible knock and then use good 91 or 93 octane gas... thats the way to go, you get the most advance that way and you know it's right... no chance of lining up with a slightly slipped mark and it'll also compensate for a loose timing chain (although if it's worn it should definatly be replaced...)...

With that... it could be a CTS or EGR... or the little backfires could be an exhaust leak... look really good... I knew I had one cause it's the only thing it could have been... took me a month to find the bastards...


you'll find it... it's always something dumb and small (but expensive)

 

Thanks I will do checks and I think I may have an exhaust leak at the manifold.

 

does your car do it right away or does it heat up 1st?

 

Anther possibility it could be your Knock sensor.
It screws in the block , into the water jacket.
The knock sensor detects pinging from preignition and when this happens it actually retards your timing.
When they go bad sometimes they will retard the timing .
It could also be the electronic spark control ( ESC) , this works in conjunction with your knock sensor.

 

My car does this too. I know exactly what you are hearing. Mine is exactly on 10* time thanks to Snap-on timing light hehehe. IT only has trouble like backfireing and sputtering from 1500-2000RPM. But there the most important; most of the time

The knock sensor is something for me too look into.(never thought of that) How can you tell if it does not work, can you unplug it?

I don't get to drive my car legally again till the end of April so I have lots of time to look. When you find the problem to your why your car is doing this please post, or send me an email. Thanks.

 

It does it at all heat ranges including cold. The backfire sounds like a muffeled Bop not like a gun shot and it does come from the intake between 1000 and 1500 RPM. I will check the knock sensor any sugestions on testing?

Thanks

 

I know the book says 10* timing. Go 14. you'll be happier and your car will LOVE IT. I had this problem right after I bought the car. I checked everything and nothing was wrong. Timing was exactly 10* so I fiddled with it and eventually got it to go 13-14 out and it settled right down. You may also have a wire crossed.?

 

14 out do you mean set the time to 24* or set it 4* out?
My timing was originally 12* out, (22* time) and it worked like garabage, it would do the same, except it wouldn't idle ontop of that. It backfired from 2500-3000 with that setup. But if you mean just turn my timing to 14* I will try that.

One more question did you time your car with the wire advanced unplugged. I know your spose too but alot of people forget to and then your car wouldn;t be st at 14* it would be more like 30* lol. Just making sure before I go out and really screw something up.

 

I will try the timing. The only thing that bothers me is that the car started having problems and no timing changes had been made.
Thanks for the help and to the guy looking to time at 10 or 14 unplug EST otherwise ECM will have control. I will try the water trick also.


Thanks

 

Yes I meant total 14* WITH THE ESC(Spark thing) DISCONNECTED.

 

Thanx, just making sure, I remeber someone telling me too do this a while ago, but the didn;t unplug the ESC, so it really causes problems with the timing....lol. Off I go to try this... Tomorrow that is.

 

On the subject of knock sensor testing. Usually It will show a code , but sometimes it wont. Only way to be sure is a hand held code computer. A friend of mine had similar problems , we tried grounding the ecm terminal for the code but it wouldnt show it. We used a hand held and whalla there it was.
As far as advancing the timing. If you have to advance your timing to get the engine to run right , it is a sure sign that your timing chain is getting worn out.

 

I Cant Drive 55
You have a good point and I would have to aggree, I know how people run these cars, and I haven't reaplaced the timing chain yet, althought I have been thinking about it, because I figure previous owners never did replace it either. LOL I will look into this, and thanks for bringing that up, the most obvious usally gets ignored till last...