Misfire/hesitation bumbling along with flashing engine light

Post by **IVIUSTANG** » 11 Jul 2009, 19:28

Hey guys,

I just got home from a 4900 KM trip from Regina to California. I noticed a pretty bad problem on the trip. It started out as a little lack of power and stutter accelerating from a stop. It then turned into an occasional stumble and loss of power on the highway. If I tried to push my car(such as passing or accelerating uphill etc) my car may respond like normally for a very brief moment then it would really bog down and was pretty much gutless; I would frequently get a flashing engine light if I loaded car; the light usually went away after a few seconds of coasting. Sometimes when cruising through towns I could also notice a surging of power up then down.

I have also noted that this problem doesn't seem nearly as bad from a cold start. When this problem is present(which is alot of the time now) the idle is very rough and fluctuates from 900 to a low of around 650 almost dieing; if I put the car in park, the idle smooths out 100%. The problem also seems exasperated by heat and elevation although perhaps the hills more than the elevation.

I drove this car the rest of the trip due to my required schedule and that fact all my fluids and temps were remaining good. If I was very smooth with my driving and gave myself lots of time the car was mostly drivable ; and it was still able to do 120 MPH with ease.

I have never done plugs/wires/dist/coil on this 1998 S70; should this be the first thing to check? How about checking my intercooler for fluid from my methanol injection system?

Any great ideas, I am sorry I am not more articulate at this time; a two week holiday is tiring

Regards,

- Jesse

mykemac · Post by **mykemac** » 11 Jul 2009, 20:49

sounds very much like a bad maf,it has a tendency to do strang things to the revs and reduce the power alot if it goes bad ,given that it starts well from cold(open loop)the car isnt using most of the sensors for engine management until engine is up to working temperature,i am pretty sure that the maf is not used until the loop closes when engine is ok temp wise,i stand corrected on this,other users feel free to comment on this,the mass flow sensor is usually located around the ar filter body

Post by **IVIUSTANG** » 12 Jul 2009, 14:13

I decided to clean the MAF sensor with electronic cleaner, I'll let you know the results.

Regards,

- Jesse

Post by **IVIUSTANG** » 20 Jul 2009, 21:28

Cleaning the MAF greatly alleviated the rough idle however it did not address the problem of the engine cutting back under load causing a loss of power and a flashing check engine light. What is the next step? I ordered a cheap code reader, but anything I should check in the meantime?

Thanks,

- Jesse

mindshadow · Post by **mindshadow** » 21 Jul 2009, 21:46

Have you noticed any white smoke coming from the exhaust? If so it probably is a busted head/head gasket.

Also it very well could be bad plug wires. A regular tune-up could fix it.

I've been in both situations and had the same symptoms, though not with a Volvo. In the case of the headgasket (which has happened twice) the car never overheated - it was actually caused by a screw-up in the factory. One was caused by a screw-up in the factory in which they had assembled the head wrong and it ended up getting a leak, the other was just bad materials in the head that caused it to expand at a different rate than the lower part of the engine and eventually after about 120k miles it caused permanent damage to the head and the head gasket.

My first car I ever owned had bad spark plugs and spark plug wires. What had happened is that instead of replacing the spark plug wires someone patched a gap in the insulation with electrical tape. Plus the spark plug gaps were off a tad.

In all of those situations my car acted almost exactly as you're describing. You can have a mechanic run a test to see if you're losing pressure in your valves caused by a head leak.

Hope that helps.

Post by **IVIUSTANG** » 22 Jul 2009, 17:45

Is there a clever way to test my spark plug wires? I also assume the the IPD wires which say they are better are in fact better than the stock?

Thanks,

- Jesse

volvo_96 · Post by **volvo_96** » 07 Aug 2009, 11:44

I had a similar problem with my 850. I checked the spark plug wires and they were fine. I then checked the coil wire and it has a lot of green build up. I believe that was causing all sorts of electrical problems, even shocked the mechanic when he touched the metal by the coil. I replaced it with a new one and all seems fine now.

Post by **IVIUSTANG** » 08 Aug 2009, 01:26

Thanks for the help, it turned out to be bad spark plug wires. I replaced it with originals and it now runs just great. It even fixed what I previously thought was transmission shudder. I did read my codes and I got a random cylinder misfire code as well as two codes stating cylinder #2 misfire. Has been 100% for a week of hard driving so far

- Jesse