Need Advice - Probably MAF Issue

[atarirx]

I was driving my 95 VR4 today and the car suddenly jolted, the closest thing I can compare it to would be if you were driving an automatic that failed to shift then suddenly slammed into gear. Only thing though is that I wasn't shifting or anything, just cruising between 60-70mph and RPMs were in the low 2ks. CEL came on for a couple seconds then turned off again, the car ran perfectly fine again after. Later in the day the exact same thing happened once more. Other than the jolt and brief CEL there were no other issues, no loss of oil pressure, no strange engine sounds, no smoke.

I checked the code history and three came up:
- Volume air flow sensor
- Intake air temperature sensor
- Barometric pressure sensor

So, before I go ahead and buy a new MAF is there anything else I should be looking at or be worried about? Thanks.

[RealMcCoy]

Being as you have codes for all three sensors contained in that housing, I would be checking the connector....

[atarirx]

The first thin I did was check the connection, unplug it and replug it. Nothing appeared to be loose and contacts looked clean. It hasn't done it again since but I've only driven about 10 miles since then. I'll probably just try swapping in a different MAF sensor and hopefully that will take care of it.

[Alex3000gt]

If you have a logger, check your TPS signal with the car off both at 0% and at WOT and let me know what you find. My car did the same thing and it ended up having a screwy TPS signal due to leaking capacitors in the ECU.

Also, report back what you see from the MAF signal at idle, is it fairly constant or is it jumping around?

Again, I am not clear if you have a logger or not, if you don't you can always *borrow* someone else's MAF and see if it fixes your problem. Unfortunately these kinds of intermittent issues are very difficult to diagnose because you cannot tell if you've fixed it unless it comes back.

[atarirx]

Unfortunately I do not have a logger, I got the codes by grounding a wire into the OBD port and counting CEL blinks. I'll pick up a MAF sensor this weekend and see if it solves it, maybe grab a TPS too just in case. Hopefully its not the ECU. If the problem never comes back I'll consider it solved.

[Rom3BreaK]

When my MAF went bad it felt and acted like an ic pipe blew off. Had been running a little lean up top in the revs on the dyno just prior. Ray said it was the first MAF he'd actually seen go bad. Gave me a new one and was good to go. Basically the car would stumble hard and eventually shut off; just my experience if it helps!

Sent from my Motorola Atrix

[Roybatty]

If you have a logger, check your TPS signal with the car off both at 0% and at WOT and let me know what you find. My car did the same thing and it ended up having a screwy TPS signal due to leaking capacitors in the ECU.

Also, report back what you see from the MAF signal at idle, is it fairly constant or is it jumping around?

Again, I am not clear if you have a logger or not, if you don't you can always *borrow* someone else's MAF and see if it fixes your problem. Unfortunately these kinds of intermittent issues are very difficult to diagnose because you cannot tell if you've fixed it unless it comes back.

Been having a similar issue periodically. I believe it is related to the tps going from partial throttle to none, coinciding with a jerk in speed reduction. I have a maftpro and was going to look at my settings on this...but it makes sense to trouble shoot the tps and related systems.

When my MAF was bad she wouldn't hold idle. Very irritating at stops. It passed all other tests in service manual.

[atarirx]

It's been a while now without any issues so I thought I'd post an update. I replaced the MAF and BOV (not that the BOV was causing these symptoms but mine was the original one and a bit leaky so why not) and that seems to have solved it. Hopefully I didn't just jinx myself. I did pick up a TPS too but so far have not installed it since all appears OK. Keeping fingers crossed...

[GTOJOE]

If you are getting codes for all 3 then it's likely that the maf lost power for a second. I would try wiggling your wiring harness etc and check the ecu for leaking caps. Also I use an led across the 2 pins and watch it blink. Same 2 pins you would use an analogue multi meter on as per service manual.

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[GTOJOE]

Edit: lol just read above post. Ignore mine since it's fixed

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