JTT

Last evening, I took a highway drive to meet a club member, about an hour of highway running on cruise (~3200 rpm), then 15-20 mins of sporty (3-5K rpm) back road running, followed by another hour of moderate backroad running. Clear, dry evening, high 60F temps. Upon hitting the highway for the return hour drive, I accelerated hard on an onramp (3/4-full throttle), at 4500 rpm, the car went into major miss, shuddering badly and refusing to rev any higher. No CEL, no temp or oil pressure issues, no smoke, or engine noise. Cruising at highway speeds, everything seemed smooth and normal. Maybe twice in an hour drive there was a split second hesitation, but still would not rev past 4500. Got home too late to look at anything.

So, this evening, I hooked up the Durametric to check for codes, Codes P0342 and P0335 showing. Tried starting car and it flashed up normally. Went for a short drive and all felt fine. Once up to temp, I tried flooring it and it went through the rev range completely normal? Ran it through the paces a couple more times, all fine. No misfires recorded on Durametric.

Only variable I can think of is I filled up with gas about 45 mins into the first leg of the trip. Could this be as simple as bad fuel? Seems odd it ran fine at lower rpms though. MAF? Any other suggestions from the knowledge base, other than divine intervention?

tom__w

Bad crankshaft position sensor or lose wire / connector.

alex.rhodes

Plugs? I just had a major shudder issue in my f150 Ecoboost. Anytime I got on boost or anytime it went over about 4000rpm it would lose power and shudder like crazy. Changed the plugs and it fixed the issue.

JTT

I should add, plugs and coil packs were replaced in last 16 months.

DBJoe996

P0342 - camshaft position sensor circuit low input
P0335 - crankshaft position sensor

One or both got out of whack and need to be checked. I would start with the camshaft position sensor since if the crankshaft position sensor goes bad the engine would stall and not restart. Get more readings from Durametric regarding these two sensors.

JTT

What additional readings can I get? Sorry, I'm still very new to Durametric. These cam deviations numbers are almost identical to what I got in Sept of last year (1.72 and .09)

JTT

Damn! Threw a MAF code today along with CEL. Any suggestions one whats going on? Could these be related, or do I have multiple faults all arising simultaneously?

Porschetech3

Sounds like you have something shorting the power to the sensors. Check the wiring diagram to see if they all share a common power supply ( which is typical). If they do ,see what all is connected to the common power supply and monitor the power supply while driving to try to determine the offending sensor (or it may be a chaffing wire)..

JTT

Thanks Porschetech3. I really appreciate the help! I do ok with mechanical stuff but have an absolute blind spot regarding electrical. Ill have a hunt in electrical diagrams when I get home and see if I can find a common supply.

DBJoe996

One thing to do is separate the electrical connectors for the engine (located on the right side of the engine compartment..the big connectors) and spray them with electrical contact cleaner.

JTT

Thanks Joe, I'll try that. I picked up some Deoxit the other day.

JTT

Update. I cleaned the main harness connector with Deoxit, along with the bank one camshaft position sensor. Also gave the MAF sensor a flush with MAF cleaner. Cleared codes and been driving it for the last couple of days (maybe 200 miles) and no codes, no shudders, all working good. I hate not finding a definitive problem but maybe it was simply a dirty connector?? I ordered a new MAF to have just in case regardless.

808Bill

That's great news!