Last night I took the car out to McDonalds. It got pretty damn cold out last night for the first time since I had the car. There was also patchy fog or like a mist all over the roads.

I was driving back from mcd's and I was really babying the car the whole way (like no throttle and shifting right BEFORE the yellow shift light) and on a straightaway I decided to accellerate through the speed limit for fun. I had just shifted into 4th and was doing 30mph (so I was between 1k and 2k), and as I rolled on the throttle a little bit, the car lost accelleration and bogged. I pegged the gas, and the car started Bucking violently so I clutched it, and downshifted to 3rd. Rev-matched, and coasted back to 30mph, and rolled on the gas. It bucked a little and was hesitating, so I floored it and it started pulling normal (but it wasnt pulling very hard). In both 3rd and 4th it was fine cruising, but didnt like being under high load at low RPM.

Back on campus, I pegged it in 1st for a quick hole shot and it ran perfectly smooth but still wasnt making power for par. I parked it and turned the radio off, and opened the door to listen to the idle. The idle sounded fine, so I revved it up in N and this strong oder of gasoline vapors and unburnt fuel hit me.

Could this be temperature / humidity related? Thanks for any ideas.

 

Sounds like you've got a fuel or timing issue.

 

Ok, well I took the car for a ride just now, and its running perfect. I will have to drive again tonight when its cold out and see if it does it again.

 

Bump. Problem getting worse: all the time now.

If you read my posts, you will know about how my car runs bad when wet. I never connected the two untill now. So, it started doing it after I washed the car, or in heavy rain. Now, it does it whenever it is warmed up above a certain temperature.

Heres what happens. The situation needs to be a High-load Low-RPM situation. For example, 4th gear, 35mph, <2k rpm. Apply full throttle, and it will buck like a raging bull. If you slowly roll on the throttle, it will run fine untill about 1/2 throttle, where it will start hesitating and jerking back and forth. Keep applying throttle, it keeps getting worse past half.

Also, it will do it in 2nd and 3rd gear. If you start rolling in first, then quickly shift to second to accellerate, it will chirp the tires it bucks so hard (and it makes a loud banging noise and clanking underneath the car while it bucks). In third, same thing. Under 2500 RPM you can definately feel it coming on, and close to 1000 rpm it is horrible.

Tonight I almost got rearended in traffic. I was starting out in 1st, and as I was getting near the tighter end of the "friction zone" of the clutch slippage, I applied gas to let the clutch out all the way. The second that high load was placed on the engine, and the tach dropped below 1k, it started shaking and stalled. Now I have been driving this car a while now, and know how to slip the clutch and drive it, so I know I didnt stall it like a n00b.

Finally, here is the last symptom. If you are parked, and in neutral, and you have the hood open. Normally, if you pump the gas (like just floor it and let off all the way again) the tach will rev to like 3-4k, and the motor will rock side to side in the engine bay. That is normal with stock mounts. Now, if I pump the gas quick, the motor will stumble and the whole engine will shake violently for a split second, then it will rev up to like 3k as normal. It idles normal too. So it only stumbles during that transition from idle to like 1000 RPM, but it still does it. And only if you peg the gas to rev it, its fine if you rev it gently.

Hopefully someone can help me, because I am stuck. I have no money to play around, let alone go to a shop. But if I can figure out the exact problem I will charge the part to the credit card. Also I am in college with no tools, and this is my DD. So if anyone is in the vincinity of Nashua, NH and would like to help me troubleshoot, the help would be appreciated.

 

I would say the IAC (Idle Air Control) . You could try cleaning it and see if that helps. Or I think a new one is like 30 bucks at the auto store.

My car surged a bit at low RPM, though never even close to what your describing. I said what the heck and bought a new IAC. Now that I think about it, it seems to have solved the problem.

 

slow-bird

Symptoms of dropping Fuel pressure.... Fuel pump or in tank hose has burst - rent fuel pressure gauge to verify that you are running 13 PSI .

//RF

 

Worth a try. Where is the schrader valve in these LO3's? Thanks.

 

There is no shrader valve (FP test port) on LO3. Rent fuel pressure test kit (most auto parts stores) You can either insert a T at TB inlet port or by removing fuel filter and inserting T there. As always user proper care when working on fuel delivery systems. TBI runs about 11 to 14 PSI.


I hope this helps

//RF

 

Hey, does autozone rent the fuel tester for free? Because if I am going to do that, I should replace the fuel filter while I am under there. Now that you gave me the idea of low fuel pressure causing it, I was thinking, the car probably has the origional fuel filter on it, or maybe they did it once. But after I bought the car I ran 2 bottles of techron in the tank. And the car still has all sorts of factory origional stuff - like factory brake fluid (black), drums/shoes, rotors, factory air filter (black). I think they really just parked the car because I got it with 47K miles and nothing maintnence wise was done to it. So, since it was her weekend cruiser, she never treated it like a DD.

But anyway, if the techron clogged the fuel filter, would that cause these symptoms too? I was thinking timing, but upon checking it it is right at 0* base. I forgot the fuel tables were pretty extreme under high load, low rpm too.

 

I would think ignition first. At low rpm and higher load on motor will demand more spark. Runs bad when wet 99% of the time is cap, rotor and good wires.

 

Those need to be replaced anyway. I already did plugs (rapidfires) but left the old wires ect on. I have never done a cap + rotor, is it hard?

Also, the wireset that is on there is pretty cool - each wire has what number spark plug it is printed on the jacket. I wouldnt mind another one like that.

But I am pretty sure the cap and rotor are origional, but I wont know untill I open it up.

 

Nope-cap and rotor is pretty straight-forward, just a couple screws on the cap and she pops off, and the rotor is right ontop and pulls off.

 

Wow - original factory stuff with 49K!

Yep - you should definitely go through ignition stuff first since it is very straight forward to R&R. Rotor and Cap should be replaced - small diameter dizzy can form carbon shorts on the side walls. If you still have issues check into fuel pressure, but replacing Fuel Filter should be a part of the course.

//RF

 

I would suggest checking your pressure...Read my thread(Surgind Idle pt3)....Similar problem

 

The other thing you might do is eliminate an EGR based problem. Disconnect the EGR vacuum hose from the TBI and plug the TBI fitting. I have seen EGR valves that the backpressure regulator valve fails or the passages become plugged, that act just as described.

 

True...I would suggest checking the FP first....

 

crap, didnt realize from 2007 :P