I'm not sure if there is a part missing pertaining to the air intake system, where can I find a picture of a regular 99 Neon engine so I can see what it looks like?

99 should be fuel injected,with a map sensor .The hose from the intake to the sensor could be unplugged. If it has a mass air flow sensor on the intake hose , it could be defective. Check your codes and go from there.

the blocks are the same, as far as heads and intakes i am not sure. even though they are both vortec engines it seems that every year vehicle engineers change something on the intake and fuel systems to raise the cafe ratings or meet EPA guidelines. the difference might be as subtle as different intake port shapes. compare the two, what i do is take pictures of one and compare it to the other.

Sounds like a cracked distributor cap or a bad coil.

if it is a trouble code for the downstream oygen sensor, or cataylist below threshold, it pertains to the catalyitic converter. I would check that if i understand you correctly.

I found the problem and 99 jimmy is running great now. the major problem was the intake manifold gaskets sucking air and causing random misfire codes(bad fuel/air ratio) but also we pulled the distributor as well because from 87-99 the drive gear was made of soft material and sure enough 3 teeth on the dist gear were almost worn right off. We also replaced this with 120$ new rebuilt unit.
Intake gasket kit is approx 100$ and no more than 2 hrs labour and the distributer is real easy to pull and replace once the intakes are off so this is a good time to check dist with little extra labour.

richard

You mention that it acts like it jumped time. By that do you mean that every few revolutions it sputters like it's thinking about starting, but fails to actually run? Have you checked to confirm you're getting fuel? Have you confirmed you're getting good spark? Have you double-checked all vacuum lines and electrical connections to make sure all the appropriate sensors are plugged in? Do you have a scan tool with datastream mode so you can make sure sensor readings are reasonable? Do you have all the intake air tubing properly installed and secure? I'm not sure if the '99 Neon uses a MAF sensor, but if so, having that unplugged or having some of the intake air tubing not tight or with a hole somewhere can cause the symptom you describe as well.

This could be due to a malfunctioing coolant sensor. It is located near the thermostat housing. It may be stuck in cold operation mode. You are probably getting bad gas mileage too. Make sure air filter is clean too. Good luck!

Your engine doesn't have a MAP sensor it has a MAF sensor , they do te same thing in different ways, that is tell the engine control how much air is entering into the eng. Here is a picture of the sensor which is in the air intake hose to the engine.

Hello, you could try pulling it and the pipe off and cleaning it before replacing it. An egr is pretty expensive. When you go to clean it use Carb cleaner.

its the air intake throttle body housing find your air filter and follow its assembly back to the throttle body this what your looking for the throttle is stuck by some build up in throttle body use some fuel injector cleaner on and in the throttle body