Hello My car runs flawlessly but when I try to drive it steady at 44/45mph it jerks? I unplugged the vacuum line coming off the egr valve that goes to the vsv and blocked it off with a screw. I also blocked the vacuum line that comes off the egr modulator that goes to the vsv with a screw as well and the car runs beautiful? I tried a new VSV and it still jerked at the 45mph speed. Anyone have an idea what is going on? ThanksNel

 

I pulled the egr valve off and the bottom port was completely clogged so I took off the other 4 bolts and pulled off the bracket inbetween the egr valve and the intake. It was all full of carbon and I cleaned it like new. I drove it around with all the vacuum lines hooked up correctly and the jerking was now barely noticeable. Im thinking about pulling the tps off to see how bad that might be?? Any other suggestions?

 

Try cleaning the throttle body and do a couple of seafoam treatments.

 

Hello Thanks for the tip. I will do that next with the throttlebody. If the egr side of it was that dirty I can imagine what the tb must look like. As for the SEAFOAM...should I insert it throught the vacuum line for the brake booster since it at the back most part of the intake or??? Thanks againNel

 

Lexls.com has detailed instruction for throttle body cleaning - it's very straight forward, but a pain in the ****, because there are two hoses connected to the TB from underneath, and they are a major pain to remove and reinstall. I ended up cutting the thicker one and replacing it, good thing they are cheap, less than a buck.

As far as seafoam threatment, add half a can to your oil, and drive the car for no more than 150 miles. Then put 1/3 can to the intake chamber, either through the brake booster or PCV, whichever is easier. You might need a friend to give you a hand with that. The way to do it, is to bring the engine to normal operating temperature, and slowly sip seaform through either PCV or brake booster hose. The only problem is once you disconnect the hose from the engine, the car will most likely stall, so you need a friend to keep RPMS around 1500-2000. And make sure to sip the seafom very slowly, otherwise you might stall or even hydrolock the engine. Once it's all sucked into the engine, shut the engine off, wait for 10 minutes, and take the car for a hard drive. Keep it in low or 2nd gear, under load at high RPMs. After the smoke is gone, take it for an oil change, and let them pour and drain one can of oil after the old oil is drained - to wash out whatever remains of loose build-up.

So far I did the seafoam threatment three times, and the last time I changed my oil it was unbelievably clean, just slightly brown, which is a sign of clean engine. Before the seafoam threatments, it used to come out all black.

 

Thanks for help!! I did a treatment of seafoam today and sipped it through the pcv hose. It not only smoked from the tailpipes but it would come out somewhere behind the engine between the rear of the manifold and the firewall. Is there supposed to be a leak somewhere down there to release exhaust? Im thinking maybe the big egr pipe where ever it hooks up to down low might have a leak and maybe this could cause the jerking?? Thanks again Off to the tb cleaning I go...

 

Sounds like cracked EGP pipe, a common problem, and a major pain to replace.

 

Hello Cleaned the throttle body(it was a mess!) and reset the ecu. I really could not notice a difference as the car ran flawlessly before except the jerking at 45mph mark. I still cant figure out what causes the car to idle so low in gear. When the engine is cold it idles at the high rpm until it gets warm and then kicks down. In gear its around 400 or less and at night when I turn the lights on it drops a tad more. Ive replaced the air filter,cleaned throttle body,cleaned the egr side of the intake as well,seafoam treatment,techron through the fuel and tried to turn the throttle position sensor up a little but then when you put it in gear it slams hard. Plugs are NGK type R and look decent as well. Thanks again Nel

 

Usually low idle issues are caused by a vacuum leak or a clogged vacuum line. Check you idle air control valve. If anything, just adjust your TPS for a higher idle, it will be a good temporary solution.

 

Rear Differential problems: e.g. gap problem,

can cause jerking whilst at speed and weird swings in engine rpms,

this problem is caused by people backing up very fast and suddenly locking up the wheels,

take a look at the rear differentials too.

 

Thanks again guys! I will look at these items and let you know my findings. Nel