Engine slightly missing? Depending, could be a sofware fix

[MadeInJapan]

There is an ECU software patch for motronic 4.4, but it's not for a bad idle. It's for a hesitation, usually when up to speed...In my car, it happened around 70~80mph on the interstate...just feels like a slight miss.

The engine hesitation is found in a handful of '98 S/V70's and C70 ECU's only with certain chasis numbers made at certain factories. The chassis numbers seem to correspond to early '98 Volvo's. By mid-year '98, the ECU issue was fixed so there is no ECU patch for any other Motronic 4.4 ECU's after this time period. Here is the information. Check your car's chassis number if you're having the symptoms mentioned above.


Remember that the directions above are for the Volvo Tech (not owner), thus the owner's manual is not for your car but for the software being provided to the dealer. Hopefully they'll have this in stock at your dealer if your car meets the criteria and seems to need a fix. If they don't have it they'll have to order it from the company, but still should be free for you (one time only, so if it's already been done to your car...they'll know from your VIN#, they won't do it again, at least not without charging you). Hope this helps.

[coedwards]

First, I know you're original post is from 2+ years ago, but I'm hoping you'll revive the issue.

I am experiencing the same "stutter" at highway speeds. I have a '98 V70XC with the 5254T engine and motonic 4.4 ECU. I figured the dealer would have the information to confirm that I was eligible for an ECU software update. They tell me that there is no update for my vehicle and that the issue is likely the transmission torque converter. They quickly offered to schedule an appointment for me to have a new transmission installed (hah!) Anyhow, I recently cleaned out the throttle body when replacing the PCV system, it's got new plugs and wires, and a new fuel filter. They recommended that I not change/flush the transmission fluid, as that might ruin the rings and worsen the problem. Any ideas? I will disclose that I have Bosch plugs and wires, and have since leaned that these cars don't do well with them... I'm ready to replace with Volvo plugs and Bougicord wires. Thanks in advance

[Ozark Lee]

I will disclose that I have Bosch plugs and wires, and have since leaned that these cars don't do well with them.

The Bosch wires are bad news but the "dollar a holler" Bosch Copper plugs are just fine so long as you gap them to 0.028 (or slightly less). Go with the Bougicord wires.

Avoid the Bosch Platinum +II or +IV multiprong versions - you can't properly gap them. Been there , done that, got the T shirt.

...Lee

[georgegrimm]

occassional engine miss: It will usually happen once everytime I drive it. It feels like one or two misses. Then it doesn't happen for another 20 minutes. It has been going on for about a year and a half. I've check plug wires, seems ok but there was some white corrison on one or two to the plug wire ends, resistance was good. I had a glitch in my throttle position sensor. I replaced it, no affect. I cleaned the throttle body, and the idle unit. And I did replace the coil and module, because I got it to miss one time by wiggling the ground wires located just below the coil-I had rested a screw drive on the side of the coil and prided the ground connections below on the fender well. I took the ground connects and soildered the crimp on connections. The coil, module, and soildering the ground connections did not cure the problem. I've checked the crankshaft sensor for resistance. Seems ok.

To sum up, the miss happens infrequent, maybe one time when I am driving the car. It did set a code one time, but I erased it. I could affort a scanner just then. However, it set a code only once. Software up patch. I could call the dealer and see if my '98 v70r qualifies. Anyway, if you got any ideas let me know. george