Dodge forum here but I have a 92 plymouth sundance that is similar to shadow. Cant find much help on other forums.

Problem is rough running on 92 Sundance 2.5 4 cyl. had ran fine but I got gas at a diff. place. from then on it will barely run it chugs barely has power will hardly run especially in drive or reverse. It will idle a little better in neutral or park.

has alot of miles on it. I checked the code by key method and only one comes up is fan relay circuit open. Have put new plugs in it but no better.

any help!

 

Welcome to Dodge Forum! You'll probably have better luck getting this question answered here in the K-car section

 

Have you tried changing the fuel filter? If its in the same spot as the K you should find it on the passenger side in font of the rear wheel, also try using a product called Sea Foam it will clean out any crud you might have in the fuel lines, also from experience I found the 2.5s run a lot smoother on 87 octane.

 

yes i have put a new fuel filter on it and seafoam!

 

If you are positive the crappy running is from the gas, try some fuel line "anti-freeze" (alcohol) to remove any water in there, and maybe some of the Chevron fuel injector cleaner.

Past that, you need air, fuel, and spark to run. If your air filter is decent and the intake hoses are clear, and you are sure of your fuel system, that leaves spark.

Make sure your plugs look good, and your wires are in good condition. Also, it might be worth unplugging the fuel injectors to see if either the harness end or the injector plug has any corrosion. Pull the distrubutor cap off and look for any dampness and to make sure the wire blades look ok. Wiggle the rotor to see if it's on tight and to see if one ear broke off the oil pump end of the distributor shaft. Look at the rotor and see if the metal contat tab is on solid. (The plastic welds sometimes give out and lets the tab come loose.)

Is your idle to low? To reset your idle, pull the vacuum line off the brake booster and start the car. It sould idle at about 3k rpm. Let it run for a minute. Shut off the engine, re-connect the vacuum line and unplug the AIS motor at the throttle body. Re- start the engine and use the stop screw in the throttle body to set the idle to about 850 rpm (it's an automatic right?) 750 rpm for a manual. Shut off the car, and plug in the AIS motor. The idle should be around 1000, or 1100 now.

Check the timing. It might be easier to pull out the airbox for this. The timing window is on the top of the trans bellhousing. I think there is a cover over the hole, from the factory, I've never seen one still in place though. Run the engine untill it's warm. Then unplug the coolant temp sensor. It's below the waterneck/thermostat. The car might want to die at this point, so have a hand on the throttle cam to keep the engine from dying. (you will have a check engine light at this point.) Connect your timing light to the #1 wire ( all the way on the passenger side) and look for the timing mark in the window. Try and idle the engine around 1000 rpm. Timing is adjusted by losening the 13mm bolt underneath the distrubutor and rotating the whole distrubutor. I can't really remember the correct timing for an N/A 2.5, The stock setting for a turbo is 12deg BTDC. Remember to tighten the hold down bolt if you loosen it, and to re-connect the coolant temp sensor.

This should give you a few things to try. Good luck.

 

Another thing to try since your problem started after you put gas in it, check your fuel cap, if its tight try replacing it. Your fuel cap is an important part of your fuel system, it helps with the pressure your engine needs to run, Ive seen a few people bring their car into the shop running rough and come to find either the fuel cap gone or loose.

 

rare aries.. I don't think the gas cap is loose,but will check.. could it be bad or would that have same effect?

4cefed.. no not positive it's the gas. pretty sure filter is ok,but will check it out. just put plugs in it,but did nothing with wires or dist cap. Brake booster vacuum line; where is that located?

I can't do much with timing;I dont have time gun.

 

Its possible it could be bad. When a cap goes bad you really cant tell, I always liked to try the cheap fixes before having to really open the wallet. When I put the cap back on I always let it click about 10 times or about a half turn.
Your brake booster vac line is found on the booster its self, this located on the drivers side of the firewall, behind the master cylinder, there should be a hose about 1/2 -3/4 in, in diameter. This only true if you have power brakes, manual brakes wont have a booster.
If your in the Albany NY area I could loan you a timing light, and see if we get you mobile again.

 

You mentioned you put new plugs in, are you positive they were the correct fit and heat range? Did you check the gap? For turbo applications, I have always gone with 0.032" I'm sure the gap for your Sundance would be on the emmisions sticker under the hood. Good luck with it.