first off, cuz im not a noob and super cool, here some info:
1999 sunfire se
2200 3spd AT (its ok if you're jealous)
just turned over 120k
recently (withing the past 2 yrs) replaced the plugs,wires, and pretty sure the coil pack


alright, so i was driving to my dads tonight and after i got off the interstate my engine started acting funny. the best way i can explain it is started to "pulse". when i first started to feel it, i kept it at a constant speed. example: i was going 60 and my rpms were at about 2600 and would jump up to 3000 (like a heart beat). i tried this as diff. speeds and it continued to do this. this lasted prolly 10 minutes. then, when i had to slow down (reduced speed zone) it started acting normally.. and had no issues the rest of the 15 mins home.

another issue i had, which started at the exact time (or at least thats when i noticed it) as the engine pulsing is my temp gauge was jumping up and down, up and down but at no consistantness. at times it even dropped all the way down to 100 and stayed there for a several seconds, then went back up.. i dont really care much about the temp gauge cuz i know it would be impossible for the temp to drop that much and i have not had any issues of the engine getting hot.

so has anyone experienced this? or have any ideas??

I am having similiar rpm spikes which I think may have to do with the plugs and/or the IAC.As for the temp. gauge IDK maybe a loose connection in the cluster or wiring somewhere else.



15.2@89mph 2.171 60ft. 9.830 1/8 R.I.P. "LULU"

computer issues? its difficult to say...

could be a mechanical problem with the 3 speed.. but they're not computer controlled so I don't know why the temp would jump around too...

i'm thinking ecu

check your battery and alt first. The ECU could be the indirect problem of low voltage.

alright, it started doing it again today on my way back from work; only this time not half as bad. it wasnt consistant much at all like yesturday. i also noticed that when going 55-60ish, if i press on the gas to accelerate, the engine doesnt kick in like it would before. before you could feel it kick in as if it shifted down a gear, but now it the rpms slowly increases.

also, just to futher clarify; the temp. gauge ONLY ACTS UP when the engine is "pulsing". otherwise it acts tottally normal which leads me to think that they are somehow related??

where can i find the throttle sensor? and what should i look for?

whiteboy: what do i need to do when you say "check my battery and alt first"... check for what??

BUMP! pass this on, tell all your friends so i can hopefully figure out what i need to check/fix/replace!!!! thank you everone!

Godspeed wrote:whiteboy: what do i need to do when you say "check my battery and alt first"... check for what??

Check your charging system for proper amp output of the alternator and load test the battery to make sure that it properly holds to a load and does not become weak...

Sometimes you can get engine performance problems from a bad battery or alternator..check those first and see what you get....also i would scan diagnostics also...CEL or NO CEL...check to see if it tripped a code at any point in time....not all codes will trip the CEL...its also a possibility you were not looking at the dash if the light appear and then went off...if it did trip a code it may be in the PCM's history.....hope this helps you any