Engine issues?

Truck4

New member
Over the past month my truck has been having some issues and seems to be getting worse. I'll be driving and the truck will buck/jolt randomly, usually at steady state driving but sometimes during acceleration. I changed my spark plugs with Denso double platinum ones shortly before the problem started happening so I can't help but wonder if I damaged my spark plug wires or something.
It's as if the engine loses power for a second and the manual transmission gets loose and then the power kicks back on and jolts the car back forward. It happens at all speeds so I don't think it's drive-train oriented (and I've already checked U-joints and fluids).
I'm looking at the Denso Spark plug wires on Rockauto and want to see if you guys have any advice before I buy em.
 
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Did you get your plugs back in the right order/sequence?
Are all your hoses hooked back up properly?
I'm assuming you went with the double ground plugs?
 
I don't remember disconnecting any hoses, but I'll check tomorrow anyways. And yeah they are in the correct sequence. The engine runs very smooth except for the seemingly random moments when it bucks. I heard that the high tension wires are prone to random short/open circuits so this is why I think it may be the wires.
 
I don't remember disconnecting any hoses, but I'll check tomorrow anyways. And yeah they are in the correct sequence. The engine runs very smooth except for the seemingly random moments when it bucks. I heard that the high tension wires are prone to random short/open circuits so this is why I think it may be the wires.

You must have really bendy arms. No way could I change all 6 plugs without disconnecting any hoses.
 
I had a similar problem a long time ago in my old tacoma and it was my throttle positioning sensor. At steady RPM's it would randomly lose power. Pretty sure there was a check engine light that popped up after awhile though.
 
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Sounds like a spark plug short to me... can be hard to figure out which plug, sometimes people have put a single wrap of electrical tap around the boot to see if it makes the problem go away, if it does, buy some new plug wires. GL
 
when it jerks does it loose RPM at all. If u can replicate it every time or just at random.
It barely loses RPM, it happens so quickly that the engine doesn't have time to slow down. And it only happens randomly, but most frequently around 2000-2500 RPM.

Then engine isn't throwing any codes and I installed a new TPS in July so I don't think it's that. It threw a code for the TPS so that was an easy diagnosis and replacement.
 
Sounds like a spark plug short to me... can be hard to figure out which plug, sometimes people have put a single wrap of electrical tap around the boot to see if it makes the problem go away, if it does, buy some new plug wires. GL

Where on the boot does the electrical tape go? Not sure I fully understand what you are describing. Where would the short most likely be?
 
Still might check the TPS with a multimeter. It took a while of driving my truck with a bad TPS before it threw a code. What you're describing sounds exactly like the problem I had.
 
I thought TPS before I opened this thread potentially. Is it always at the same throttle application/steady cruising that it occurs?

Apply the multimeter and do a sweep to look for flat spots.

If you DO end up getting plugs, there are several vendors on ebay who sell OEM wires and plug sets for the best prices. I bought NGK oem wires, I believe they were like $52 shipped with a full set of factory plugs. I'll dig it up for you..

This is what I purcased; http://www.ebay.com/itm/190507981905?_trksid=p2060353.m2749.l2649&ssPageName=STRK:MEBIDX:IT
They were the best priced/most reputable deal I could find at the time a few months ago.
 
Still might check the TPS with a multimeter. It took a while of driving my truck with a bad TPS before it threw a code. What you're describing sounds exactly like the problem I had.

Absolutely can be the TPS.....cheap OEM part, replace it as it may still test fine.
 
Where on the boot does the electrical tape go? Not sure I fully understand what you are describing. Where would the short most likely be?

the boot... where the rubber bit goes down the hole to the spark plug. I've only read about this on here, i've never done it because my shorts with the pug wires are always obvious, like the wore contact come out of the plug wire.
 
Ok few things to check. #1 spark plug to make sure no cracked porcelain #2 spark plug wires, these seem to not like aftermarket ones, but Toyota wires can be counted on for min 10yrs 100k miles #3 injector problems these also can have the intermittent jump,hesitation, bump feel #4 throttle sensor and all of these can be the culprit and not immediately set a code for awhile.
 
Was the replacement TPS OEM or aftermarket?

I ordered the "STANDARD MOTOR PRODUCTS TH207T" TPS from rockauto, so I'm assuming that is aftermarket. I'll do a sweep with the multimeter tomorrow and see if there are any parts that don't read correctly.
 
Ok few things to check. #1 spark plug to make sure no cracked porcelain #2 spark plug wires, these seem to not like aftermarket ones, but Toyota wires can be counted on for min 10yrs 100k miles #3 injector problems these also can have the intermittent jump,hesitation, bump feel #4 throttle sensor and all of these can be the culprit and not immediately set a code for awhile.

I've been driving it around and it is definitely getting worse. Is there a way to check for injector problems or do I have to replace them and see if the problem goes away? That's what I am doing with the Spark plug wires this week.
 
Make sure your spark plugs are fully engaged in the plug boots. Also, the boots under the coil packs have been know to arc through. When I did my plugs and wires I also replaced the boots
 
Sorta

I've been driving it around and it is definitely getting worse. Is there a way to check for injector problems or do I have to replace them and see if the problem goes away? That's what I am doing with the Spark plug wires this week.

If you have a scan tool that reads cyl misfires you can look at the misfire % and figure out which cyl is misfiring. Then you can swap injectors then see if the misfire changes with the injector. Other than that not a real efficient way to test an intermitten injector problem. (assuming that is your problem).
 

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