996spdFormula

i have 99 ponitac formula, its bone stock no mods just a cut out, my car has been running excellent uptil yesterday when it started idling low then it would ilde high and keep doing the same thing at a stop, i also noticed that the car would kinda like sputter like hop kinda thing, and also it kinda hesitates when runniing it at lwo rpms. now when i gun it at high rmps it doesnt seem to sputter or hesitate but al low rpms it does. i also noticed that my gas mileage sucks. and at low rmps when i gun it it misfires a little you can hear it its pretty noticable....so i scan the car and it throws me back no codes at all. NONE. So i dont know what to do.... i was thinking spark plugs. o2's, egr valve, clogged cats, or clogged fuel injectors,,,not quiet sure....anybody have any suggestions feel free to voice your opinion!

Quickin

Hesitating, stalling, sputterring: texbook bad O2's, but to all of a sudden start, probably not.

No (SES) is wierd. My O2's were both completely shot and I got no SES but it showed up on a scan.

If you have no codes I would change the fuel filter. A clogged filter will only sputter and make the engine run crappy at low rpms and idle, since the fuel pressure is lower. But when you get into the throttle the fuel pressure increases enough to overcome a clog that is building up.

Run a can of Sea Foam in your gas tank too, maybe the injectors need a cleaning.

Could also just be a bad tank of gas.

.

txh0tb0i972

iTrader: (63)

im getting the same problem but my problem occured when i hit a puddle of water and now i get a random misfire code p0300 but it doesnt tell me what cylinder its coming from i have replaced my wires , my spark plugs and my fuel filter but none of it seems to be the problem so if some one can help me out aswell itll be very nice

razorclaw99

iTrader: (7)

its plugs or wires

txh0tb0i972

iTrader: (63)

look what i found about my problem on my 300 code... well because im not getting what cylinder i had a daily mechanic go in there and he told me it was going to be a crankshaft postion sensor he said that the engine was so hot when it had impact with the water it fried that sensor and i did some research and look what i found .... could this possibly solve our problems .... by the way i have changed my plugs and wires it does the same so thats not the answer to my problem but maybe 4 996spdformula

http://gearchatter.com/viewtopic8880...9c573f2a1829c2

Quickin

Could be the CPS but you'd get an SES light. If you don't get an SES light, which is possible, it will show up on a scan. Bad CPS will cause horrible backfires, spitting and stalling. Than it will run perfect again, than run like **** again.


.


.

996spdFormula

ummmmm changed the fuel filter same result...and did a seafoam not a whole lot of smoke came out when drove it but it was enough to notice deiffrence in the car felt a little better car still sputters a lil bit doesnt hesiatate as much and still misfires a lil bit when i gun it a low rmps....maybe a plug or a wire, maybe clogged cats, i dont know anymore idea guys i plan on checking plugs and wires tomorrow, but if it was a cylinder misfire wouldnt it thorw me a code.....i feel the hesitation sputter and misfire but no code.....HELP! any suggestions....if not im taking it to the dealer see what they tell me...lil more info 99 formula just hit and passed 85,000 miles,,,,can it be the egr valve cuz when i did scan it did say egr valve not ready...can that be the issue...has anyone experienced that.......can it be o2's possible any suggestions please feel free to give your 2 sense....gottta get that daily driver running in conditions again

txh0tb0i972

iTrader: (63)

i had a dude tell me it was my cps and my egr valve.... he said since i didnt have one it was missing with my o2s and its throwing it off so im going to see if we have one at the job

txh0tb0i972

iTrader: (63)

hey man u should try changing your cps i changed it today..... i havent really drove it yet but it sounds a whole lot better then what it use to..... and im not getting a 300 code any more..... so hopefully tomorrow i can find out if thats the prob...... i have to buy another freeze plug so thats the reason i couldnt really drive it...... i took it off and it had some kind of silicone or something to stop the air.... and now it sucks in air but i put a shirt over it..... so i can hear it and its alot better

txh0tb0i972

iTrader: (63)

well i found the problem to my car maybe u should try it..... unplug a o2 and drive it around unplugged.... and if it drives right thats your problem..... if thats not it switch to another o2 ....... and of course plug the other one in...... it worked for me it was an 02 .... hopefully this can help u ...... just passing on info i got from a local friend

UCFWS6

iTrader: (4)

I've had similar problems twice and it was a different problem both times. First occurence was the o-ring on the EGR not sealing properly, fixed everything instantly. Second time I hit water and ruined o2's after replacing those everything was back to normal and misfire codes went away.

txh0tb0i972

iTrader: (63)

they same here i had a leak through the egr valve.... then i hit the water... and ruined the o2 now the 300 code is off....