K guys im really getting pissed off lately with the car. Besides being a cop magnet its got its probs. But hey u still gotta love these things ha. K heres the problems

1.)Miss and Stumble
Car has a new tune-up(spark plugs,cap, rotor,oil change, tps checked)When i start the car in the morning it stumbles bad but as soon as it warms up a bit it seems to run fine. However, it still has a miss and is a bit shaky at idle. I think its the coolant temp sensor what u guys think.

2.) Failed EMissions
Hydrocarbons was the only one i fialed got a 2.0 and the standard is a .80. Im gonna go about turning down the timing its advanced 6 degrees and putting in a new 02 sensor. Not sure how bad the cat is but it doesnt smell so i dont think it could be too bad. ANy other suggestions on what could be making these numbers high?

3.) Uncooperating parts
My car is equipped with a 2500 stall and 2.77 gears. I was wondering if this would be making my car run slower because the parts are mismatched. Gonna change the rear but the 9 bolts are expensive.

 

6* BTDC is spec for the stock calibration...no need to change anything there.

The miss and high HC are probably related.

Did it have the miss before the tuneup? If so and it seems you've changed everything excepty the plug wires...these can be checked with an ohm meter, as can the CTS.

The 2500 stall is probably only helping the performance with the 2.77's.

 

Sorry its got 12* advanced timing. Yes, the car had the miss before the tune-up and im gonna repalce the spark plug wires jsut for the hell of it. Also, do u guys think the coolant sensor could be my problem. Im sure i can tell when the car goes into closed loop or not or if it does at all.

So u dont think the stall with the highway gears is making me more sluggish? THats good i guess, but im gonna be getting some new gears soon. Any word on that spacer from 9 bolt were u can fit the 2 series carrier up with 3 series gears?

 

Idle misfires are a PAIN IN THE A$$!!!

I had one that plagued me for over a year on my 1971. Finally, I had the idea to blow out all of the fuel tank vent lines and change the charcoal cannister and that did the trick.

For you though, maybe an injector is malfunctioning?

Maybe a bad spark plug wire? Ohm out your wires with a ohmmeter and see if any are way off from the others. That could be the culprit.

 

Thanks for the reply guys, i just replaced the o2 sensor and turned down the timing back to stock. Car still smells like its running rich :-(. Took the car to local muffler shop and they said the converter wasnt rattling and didnt seem like it needed to be replaced. I bought some accel plug wires and accidently got universal ones. Do i need a special tool to put these together? Is it hard to test the injectors besides having to take the intake off what else do i need? ANy other reasons y i failed?

Also, the cold start problem is still there. This problem has had me stumped for a long time. The car seems to go into closed loop (idle goes down and becomes less rumbly). Hoever, in the morning when it starts up it stumbles, shakes, and hesitates badly. As soon as it warms up problem is gone. However, if the temp gets to about 220 or a bit lower the car runs like crap. Any suggestions with this? Coolant Sensor?

Appreciate the help Guys

 

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I have a similar issue. I have a miss at idle, and that is it. I have contributed mine to two things. 1) exhaust leak where the SLP y-pipe meets the stock manifolds (I broke one bolt, and only one holding it on. Yeah I know I need to fix it, but w/ the new motor going in really soon, I am too lazy.) causing the 02 to sense the fresh air and add more fuel causing the miss, or 2) Coolant Temp Sensor in the intake. On the scantool, the ECM is reading 245* F when warmed up, which isnt' right b/c the in dash guage is at 180, and water hoses via infared are around 180. Heck cold start it reads 100* when its 45* outside.

I need to replace that sensor and see what it does.

 

Timing will mess with emissions...
I had 12 * advanced as well...even with a cat I couldn't pass ,but setting back to 6* it pass fine (maryland emissions btw)
Coolant temp sensor could be the problem ,especially if its reading one thing and the car is doing another..it could throw the computer off...mine in the morning( sometimes) has a slight stumble at part throttle but I nail it, it goes fine...(a little
pinging sometimes going up a hill though)..i have a new distributor,wires ,plugs...once it heats up a little ..runs great.
I wouldn't think a 2500 stall with 2.77 gears would hurt...help more than anything I would imagine...Since you don't have the gear to get you out of the hole at least you can bring it out a little higher rpm..steaper gears like 3.27-3.73's would give great improvements though..traction would become an issue .