98 monte carlo problems.

[coryg]

alright.. so my pos monte has been really pissing me off lately.
new parts in the last two months are both cv shafts, a new shift module, all new abs system, the vacuum control for the heat, intake gaskets, and most of the relays in it are new as well as new wheels and tires and struts, plugs, wires and coil packs as well as a new cam sensor and the fuel pump is maybe 4 months old. ... now i dont know what to do with it. it recently started jerking pretty bad.. it happens only for about 3-5 seconds and stops but this happens prbably twice every other time i drive it. i noticed that when it starts jerking the rpms jump and drop alot like it did when the cam sensor went out. anyone have an idea? i hooked my scanner up to it and there is no code.. it doesnt have a check engine light on or anything. any ideas?

 

[TomJenks]

What engine is in it? The 3100 or the 3.8. When u say jerking, do you mean like the engine is cutting out, or is it trying to lunge forward while you're stopped? If its the 3.8 motor, it could be the crank sensor and/or harmonic balancer.

 

[coryg]

its a 3.1, and yeah, its kinda like the engine cuts out. i think i know whats wrong with it. its a chevy. seriously though im stumped. its pretty much like a new car. i shouldnt be having these problems with it. its yet to hit a 100k and i drive it respectfully. when its not jerking its a beautiful running car. to be more specific, when it jerks, the rpms will go from about 2100 to 800 and then up to 1500 and so on.

 

[coryg]

and it cant be the cam sensor its only like a month old, and whatever it is thats causing it is not throwing any codes.

 

[TomJenks]

If its surging at idle, vacuum lines could be the culprit. Theres a big wad of them that is over by the throttle body. Check the main one that goes down under the coil packs on the back valve cover and comes from the air intake tube. Make sure it is pushed into the valve cover all the way, or that it doesn't have a break in the line. Broken vacuum lines will cause intermittent drivability issues on those motors and won't throw a code all the time. also pull the egr valve and clean the valve up up real good. I've seen alot of those that get gunked up from people that drive mostly short distances.

Pull the MAF sensor off and make sure it is clean.

You said you put a new fuel pump on. I assume you've replace the fuel filter also. If it has fuel problems that are causing the stumbling, sometimes it won't show codes either. Do you have a spare ignition module you could swap out?

 

[coryg]

it doesnt surge at idle. only when going at about 55-59mph

 

[coryg]

maf is also clean. i thought that might have been the problem but it wasnt. we also did a leak down test on all the vac lines and nothing there, maybe it could be ign module. ill have to look.

 

[coryg]

i just dont understand. before me, this was a one owner car that was very well maintained.

 

[shane96ranger]

Have you checked your ground connection? A bad ground would cause all of that. And GM's retarded terminal's a terrible, I had non stop issues when I owned a Cadillac a few years ago.

 

[coryg]

im sure theyve been gone over my dads been a mechanic for 30 years and hes just as stumped as i am.

 

[shane96ranger]

That sucks man, my Cadillac did just what you're explaining and it was a bad ground. Do what I did; it's a GM, put a bullet in it.

 

[coryg]

yeah. im not a gm person at all. first one ive owned and never again. its a nice looking car, but that doesnt do me any good. i might just try to sell it and get a second ranger for dd'ing

 

[coryg]

lol i would but im sure the right chevy sucker would want it, im eyeing a 92 ranger with a 4.0 and 4x4 5spd for 350 from a guy i went to school with...

 

[shane96ranger]

I loved my Cadillac when I got it, but in a years time and a new transmission I was done with it. What a POS. I know the guy I sold it to and it has had 2 tranny's and a new motor since then. It is currently dead again with a bad ECU. It's a 94 STS with a Northstar.

 

[coryg]

those northstars are crazy. a guy down the road from me has one in his fiero, that thing is a rocket.