hey guys, been on here for a while but havent really posted. usually find what i need by searching thru the forum, but i am stumped as to what the issue is.

its a 99 ls with the 3.1 ltr, with very high milage, 221,000 to be exact. recently started to get a bad sputter, hesitation when idling, and even when driving. the rpm range doesnt matter, it just comes and goes, but lately it is happening and not stopping. this weekend, i decided to dive in and see if i could fix it, but seems like i only made it worse. i changed all six fuel injectors, all six plugs, new set of plug wires, cleaned out the egr port, new pcv valve, and replaced the air filter. only thing i didnt get to get done was putting on the new fuel filter. like i said, the thing runs worse now with all the new parts, then it did with the old ones on it. the cel is on, but havent had a chance to get it over and have the codes read, probably gonna do it on tuesday, but was wondering if anyone had any ideas on what else i can check, change, etc etc.

the car has been a very good car, im the second owner of it, and use it for daily transportation back and forth to work. but i really dont wanna start throwing a ton of money into it with it having so many miles on it. so any ideas or advice is greatly appreciated.

 

Do you notice any white smoke out the exhaust OR does your temp begin reading very high (as in close to over heating)?

I ask because I dealt with a 3100 that when it was first started from a cold start, it idled rough but in a few feet of driving it ran 100% fine. It later developed temp spiking due to an air pocket in the system. I had to have a professional eventually diagnose the problem, but it turned out to be bad set of head gaskets. Changed them and the car ran great.

Before going crazy, get the CEL codes and let us know what they are. It may be something simple.

BTW - Since you said it's running worse since you did a lot of work on it, verify your firing order from coils to plugs are correct and that your injectors are plugged in properly. Also, I assume you used new injector O-rings? If not, you may have a vac leak of they were too worn OR if you did not get the injectors seated all the way.

 

MAF? IAC? Plugs/wires? Check engine light?

 

no, no white smoke. temp is normal, not overheating, coolant level is spot on. i did use brand new o-rings when i installed the new injectors. got an appointment tomorrow to bring it to the garage and hook it up to the obd machine, so as soon as i know, i will post up what i find out. a friend said it could possibly be the catalytic converter could be clogging up. stay tuned...

 

well got the monte over to the garage today, and had my friend put it on the obd machine, and he came back with a map sensor code. now this is where i feel like a complete moron, idiot, whatever name suits... we looked under the hood and come to find out, the plug wasnt connected all the way. it was loosing connection. the little tab that clips on was broken off and the connector vibrated loose. pushed the plug all the way in, put some black tape around it to hold it secure and bam, the monte runs great once again. my friend burst out laughing, and i felt like an ***. hahahaha, but hey at least its running great again. simple things cause such headaches.

 

Don't let it get to you. At least it was an EASY fix.