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AZTechBrian, ASE Certified Technician
Category: Dodge
Satisfied Customers: 708
Experience:  Owner
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Have a 2005 Grand Caravan. 3.8L. Experiencing hesitation

Customer Question

have a 2005 Grand Caravan. 3.8L. Experiencing hesitation between 1200 and 2000rpm. Regardless what speed only hesitates under LOW load and low rpm's. Replaced EGR, cleaned throttle body, added seafoam to help with cleaning injectors. I cannot tell if hesitation is fuel related or tranny. Last code check revealed no tranny issues. Ideas???
Submitted: 1 year ago.
Category: Dodge
Expert:  AZTechBrian replied 1 year ago.

Hello. It's possibly a vacuum leak. Do you have any trouble codes at all?

Customer: replied 1 year ago.
I went and checked codes. P420, P301 cyl 1 misfire, P403 egr circuit, P406 egr. I just put new plug wires on after the code read. Also, put about 75 miles on since egr was replaced last thought it would have reset that code by now.
Customer: replied 1 year ago.
Still hesitating after wires were replaced. FYI
Expert:  AZTechBrian replied 1 year ago.

Ok. Your probably dealing with a vacuum leak. Sometimes it takes quite a while for a code to clear itself. if possible, try clearing them with a scan tool and see what comes back. 0403 is the egr control solenoid. if you want, I can provide you with the diagnostic procedure for those codes tomorrow.

Expert:  AZTechBrian replied 1 year ago.

are you able to check the fuel trims? or attach a vacuum gauge and see what the engine vacuum does? would like to determine the cause of that misfire.

Customer: replied 1 year ago.
I will get the codes cleared tonight. I will let you know what comes back! Also,I will investigate how to check fuel trims and how to attach a vacuum gauge as I have never tried either.
Customer: replied 1 year ago.
Forgot to tell you the wires were in awful shape. It appears one on the rear side of the motor was spliced together. Pretty hack job and I am embarrassed I did not notice when changing the plugs. BTW what is the location of cylinder 1?
Expert:  AZTechBrian replied 1 year ago.

you can attach it to any vacuum line on the intake manifold. you can use a T fitting. You can also remove the brake booster vacuum hose and use that vacuum supply, as long as you have a way to reduce it down. you will need the proper adapter for either option. The vacuum gauge comes with a few different adapters. fuel trims can be monitored using a scan tool. high trims will indicate to us that your lean. If the trims normalize when you increase rpm, that will indicate to us that you probably have a vacuum leak.

Expert:  AZTechBrian replied 1 year ago.

Your engine is sideways mounted. Cylinders 1 3 and 5 are in the rear and 2 4 and 6 are in the front. Cylinder 1 is the rear cylinder furthest to the passenger side of the van.

Expert:  AZTechBrian replied 1 year ago.

If the wires were really bad, you should probably change the cylinder 1 spark plug again. I know you already replaced it but the bad wire may have damaged the new plug. Or, you can swap the plug in cylinder 1 with another cylinder, clear the codes and see if the misfire moved to the cylinder you swapped plugs with.

Customer: replied 1 year ago.
Good catch. I will do that first. Replace it I mean.
Expert:  AZTechBrian replied 1 year ago.

Great. Let me know the outcome. Once we figure out that misfire, i think our problem will be solved. The bad wire could have very easily damaged the ignition coil as well.

Customer: replied 1 year ago.
Got sucked back to the world of work. Working on your suggestions today. FYI changed plugs and wires and engine light has NOT come back on.
Expert:  AZTechBrian replied 1 year ago.

well, that's a good sign! Glad it worked out!